A024379 a(n) = 3rd elementary symmetric function of the first n+2 positive integers congruent to 1 mod 4.

45, 812, 5130, 20460, 62335, 158760, 355572, 722760, 1361745, 2413620, 4068350, 6574932, 10252515, 15502480, 22821480, 32815440, 46214517, 63889020, 86866290, 116348540, 153731655, 200624952, 258871900, 330571800, 418102425, 524143620

Offset

1,1

Links

Table of n, a(n) for n=1..26.

Formula

From R. J. Mathar, Sep 15 2009: (Start)

a(n) = n*(2*n+3)*(n+2)*(n+1)*(4*n^2+8*n-3)/6.

G.f.: (27*x^3+391*x^2+497*x+45)*x/(1-x)^7. (End)

Maple

S := proc(n, L) mul(x+i, i=L) ; expand(%) ; coeftayl(%, x=0, nops(L)-n) ; end: A024379 := proc(n) S(3, [seq(4*j+1, j=0..n+1)]) ; end: seq(A024379(n), n=1..40) ; # R. J. Mathar, Sep 15 2009

Crossrefs

Sequence in context: A264138 A293971 A341427 * A134290 A359933 A341573

Adjacent sequences: A024376 A024377 A024378 * A024380 A024381 A024382

Keyword

nonn

Author

Clark Kimberling

Status

approved