OFFSET
0,2
COMMENTS
Binomial transform of A069039. - Paul Barry, Feb 19 2003
If X_1, X_2, ..., X_n are 2-blocks of a (2n+1)-set X then, for n >= 5, a(n-5) is the number of (n+6)-subsets of X intersecting each X_i, (i = 1, 2, ..., n). - Milan Janjic, Nov 18 2007
REFERENCES
M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 795.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy].
Milan Janjic, Two Enumerative Functions
Index entries for linear recurrences with constant coefficients, signature (14,-84,280,-560,672,-448,128).
FORMULA
G.f.: (1-x)/(1-2*x)^7.
a(n) = 2^n*binomial(n+5, 5)*(n+12)/12. [See a comment in A053120 on subdiagonal sequences. - Wolfdieter Lang, Jan 03 2020]
a(n) = Sum_{k = 0..floor((n+12)/2)} C(n+12,2*k)*C(k,6). - Paul Barry, May 15 2003
E.g.f.: (1/45)*exp(2*x)*(45 + 495*x + 1125*x^2 + 900*x^3 + 300*x^4 + 42*x^5 + 2*x^6). - Stefano Spezia, Jan 03 2020
MAPLE
seq(2^(n-1)*binomial(n+5, 5)*(n+12)/6, n=0..25); # G. C. Greubel, Aug 27 2019
MATHEMATICA
Table[2^(n-1)*Binomial[n+5, 5]*(n+12)/6, {n, 0, 25}] (* G. C. Greubel, Aug 27 2019 *)
LinearRecurrence[{14, -84, 280, -560, 672, -448, 128}, {1, 13, 98, 560, 2688, 11424, 44352}, 30] (* Harvey P. Dale, Sep 26 2024 *)
PROG
(Magma) [2^(n-1)/6*Binomial(n+5, 5)*(n+12) : n in [0..25]]; // Brad Clardy, Mar 10 2012
(PARI) vector(26, n, 2^(n-2)*binomial(n+4, 5)*(n+11)/6) \\ G. C. Greubel, Aug 27 2019
(Sage) [2^(n-1)*binomial(n+5, 5)*(n+12)/6 for n in (0..25)] # G. C. Greubel, Aug 27 2019
(GAP) List([0..25], n-> 2^(n-1)*Binomial(n+5, 5)*(n+12)/6); # G. C. Greubel, Aug 27 2019
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
More terms from James A. Sellers, Aug 21 2000
Name clarified by Wolfdieter Lang, Nov 26 2019
STATUS
approved