|
Search: id:A038764
|
|
|
| A038764 |
|
a(n)=C(n,0)+6C(n,1)+9C(n,2). |
|
+0
7
|
|
| 1, 7, 22, 46, 79, 121, 172, 232, 301, 379, 466, 562, 667, 781, 904, 1036, 1177, 1327, 1486, 1654, 1831, 2017, 2212, 2416, 2629, 2851, 3082, 3322, 3571, 3829, 4096, 4372, 4657, 4951, 5254, 5566, 5887, 6217, 6556, 6904, 7261, 7627, 8002, 8386, 8779, 9181
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
COMMENT
|
Coefficients of x^2 of certain rook polynomials (for n>=1; see p. 18 of the Riordan paper). - Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 08 2004
|
|
REFERENCES
|
S. J. Cyvin et al., Unbranched catacondensed polygonal systems containing hexagons and tetragons, Croatica Chem. Acta, 69 (1996), 757-774.
J. Riordan, Discordant permutations, Scripta Math., 20 (1954), 14-23.
|
|
FORMULA
|
Binomial transform of (1, 6, 9, 0, 0, 0, .....). a(n)=(9n^2+3n+2)/2. G.f.(1+4x+4x^2)/(1-x)^3. - Paul Barry (pbarry(AT)wit.ie), Mar 15 2003
|
|
CROSSREFS
|
Reflection of A060544 in A081272.
Second column of A024462. Also = A064641(n+1,2).
Shallow diagonal of triangular spiral in A051682.
Sequence in context: A063130 A033954 A081274 this_sequence A132438 A010001 A014073
Adjacent sequences: A038761 A038762 A038763 this_sequence A038765 A038766 A038767
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
njas, May 03 2000
|
|
EXTENSIONS
|
More terms from James A. Sellers (sellersj(AT)math.psu.edu), May 03 2000
|
|
|
Search completed in 0.002 seconds
|
