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Search: id:A002414
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| A002414 |
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Octagonal pyramidal numbers: n(n+1)(2n-1)/2. (Formerly M4609 N1966)
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+0 17
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| 1, 9, 30, 70, 135, 231, 364, 540, 765, 1045, 1386, 1794, 2275, 2835, 3480, 4216, 5049, 5985, 7030, 8190, 9471, 10879, 12420, 14100, 15925, 17901, 20034, 22330, 24795, 27435, 30256, 33264, 36465, 39865, 43470, 47286, 51319, 55575, 60060, 64780
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Number of ways of covering 2n x 2n lattice with 2n^2 dominoes with exactly 2 horizontal dominoes.
Equals binomial transform of [1, 8, 13, 6, 0, 0, 0,...]. - Gary W. Adamson (qntmpkt(AT)yahoo.com), Jun 14 2008
Contribution from Johannes W. Meijer (meijgia(AT)hotmail.com), Mar 07 2009: (Start)
Sequence of the absolute values of the z^1 coefficients of the polynomials in the GF3 denominators of A156927. See A157704 for background information.
(End)
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REFERENCES
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N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
S. Plouffe, Approximations de S\'{e}ries G\'{e}n\'{e}ratrices et Quelques Conjectures, Dissertation, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.
A. H. Beiler, Recreations in the Theory of Numbers, Dover, NY, 1964, p. 194.
L. E. Dickson, History of the Theory of Numbers. Carnegie Institute Public. 256, Washington, DC, Vol. 1, 1919; Vol. 2, 1920; Vol. 3, 1923, see vol. 2, p. 2.
M. E. Fisher, Statistical mechanics of dimers on a plane lattice, Physical Review, 124 (1961), 1664-1672.
P.W. Kasteleyn, The statistics of dimers on a lattice, Physica, 27(1961), 1209-1225.
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LINKS
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T. D. Noe, Table of n, a(n) for n=1..1000
S. Plouffe, Approximations de S\'{e}ries G\'{e}n\'{e}ratrices et Quelques Conjectures, Dissertation, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.
S. Plouffe, 1031 Generating Functions and Conjectures, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.
Index entries for sequences related to dominoes
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FORMULA
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a(n) = odd numbers * triangular numbers - Xavier Acloque Oct 27 2003
a(n)= n*(n+1)*(2*n-1)/2, n>=1. G.f.: x*(1+5*x)/(1-x)^4.
(2*n+1)*binomial(2+n,2). - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 12 2006
a(n) = A000578(n) + A000217(n-1) - Kieren MacMillan (kieren(AT)alumni.rice.edu), Mar 19 2007
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EXAMPLE
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a(2) = 9 since there are 9 ways to cover a 4 X 4 lattice with 8 dominoes, 2 of which is horizontal and the other 6 are vertical.
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MAPLE
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A002414 := n-> 1/2*n*(n+1)*(2*n-1);
A002414:=(1+5*z)/(z-1)**4; [Conjectured by S. Plouffe in his 1992 dissertation.]
Contribution from Johannes W. Meijer (meijgia(AT)hotmail.com), Mar 07 2009: (Start)
nmax:=38; for n from 0 to nmax do fz(n):=product((1-(k+1)*z)^(1+3*k), k=0..n); c(n):= abs(coeff(fz(n), z, 1)); end do: a:=n-> c(n): seq(a(n), n=0..nmax);
(End)
a:=n->sum (j*(n+1)+n*(j-1), j=0..n): seq(a(n), n=1..40); # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 18 2009]
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MATHEMATICA
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f[n_]:=6*n+1; s1=s2=0; lst={}; Do[a=f[n]; s1+=a; s2+=s1; AppendTo[lst, s2], {n, 0, 6!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Jun 25 2009]
Table[Sum[(n^2 - i), {i, 0, n}], {n, 1, 40}] [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jul 11 2009]
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CROSSREFS
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Cf. A004003.
Cf. A002411.
Cf. A093563 (( 6, 1) Pascal, column m=3). A000567 (differences).
Contribution from Johannes W. Meijer (meijgia(AT)hotmail.com), Mar 07 2009: (Start)
Cf. A156927, A157704.
(End)
Sequence in context: A005919 A084370 A000439 this_sequence A000440 A161684 A054310
Adjacent sequences: A002411 A002412 A002413 this_sequence A002415 A002416 A002417
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KEYWORD
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nonn,easy,nice
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
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Additional comments from Yong Kong (ykong(AT)curagen.com), May 06 2000
More terms from Larry Reeves (larryr(AT)acm.org), May 09 2000
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