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Search: id:A065101
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| A065101 |
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a(0) = c, a(1) = p*c^3; a(n+2) = p*c^2*a(n+1) - a(n), for p = 3, c = 2. |
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1
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| 2, 24, 286, 3408, 40610, 483912, 5766334, 68712096, 818778818, 9756633720, 116260825822, 1385373276144, 16508218487906, 196713248578728, 2344050764456830, 27931895924903232, 332838700334381954
(list; graph; listen)
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OFFSET
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0,1
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LINKS
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Harry J. Smith, Table of n, a(n) for n=0,...,100
Index entries for sequences related to linear recurrences with constant coefficients
Tanya Khovanova, Recursive Sequences
J.-P. Ehrmann et al., Problem POLYA002, Integer pairs (x,y) for which (x^2+y^2)/(1+pxy) is an integer.
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FORMULA
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G.f.: 2/(1-12*x+x^2).
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MATHEMATICA
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a[0] = c; a[1] = p*c^3; a[n_] := a[n] = p*c^2*a[n - 1] - a[n - 2]; p = 3; c = 2; Table[ a[n], {n, 0, 20} ]
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PROGRAM
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(PARI): polya002(3, 2, 18). For definition of function polya002 see A052530.
(PARI) { p=3; c=2; k=p*c^2; for (n=0, 100, if (n>1, a=k*a1 - a2; a2=a1; a1=a, if (n, a=a1=k*c, a=a2=c)); write("b065101.txt", n, " ", a) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Oct 07 2009]
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CROSSREFS
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Cf. A052530.
Sequence in context: A019520 A061190 A002006 this_sequence A052739 A135389 A065513
Adjacent sequences: A065098 A065099 A065100 this_sequence A065102 A065103 A065104
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KEYWORD
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easy,nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), Nov 12 2001
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EXTENSIONS
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More terms from Marc LeBrun (mlb(AT)well.com) and Robert G. Wilson v (rgwv(AT)rgwv.com), Nov 12 2001
Gen. func. from Floor van Lamoen (fvlamoen(AT)hotmail.com), Feb 07 2002
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