A004324 Binomial coefficient C(3n,n-6).

1, 21, 276, 2925, 27405, 237336, 1947792, 15380937, 118030185, 886163135, 6540715896, 47626016970, 343006888770, 2448296039700, 17345898649800, 122131734269895, 855420636763836, 5964720367660956

Offset

6,2

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. 828.

Links

Seiichi Manyama, Table of n, a(n) for n = 6..1000

Milan Janjic, Two Enumerative Functions.

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].

Formula

D-finite with recurrence -2*(2*n+5)*(n-6)*(n+3)*a(n) +3*n*(3*n-1)*(3*n-2)*a(n-1)=0. - R. J. Mathar, Jan 13 2025

Mathematica

Table[Binomial[3n, n-6], {n, 6, 30}] (* Harvey P. Dale, Oct 20 2015 *)

Crossrefs

Sequence in context: A022745 A225967 A334529 * A243421 A028053 A223996

Adjacent sequences: A004321 A004322 A004323 * A004325 A004326 A004327

Keyword

nonn,easy,changed

Author

N. J. A. Sloane

Status

approved