A024390 [ (4th elementary symmetric function of S(n))/(3rd elementary symmetric function of S(n)) ], where S(n) = {first n+3 positive integers congruent to 1 mod 4}.

0, 2, 5, 10, 15, 21, 28, 37, 46, 56, 67, 80, 93, 107, 122, 138, 156, 174, 193, 213, 235, 257, 280, 304, 330, 356, 383, 411, 441, 471, 502, 534, 568, 602, 637, 673, 711, 749, 788, 828, 870, 912, 955, 999, 1045, 1091, 1138, 1186, 1236, 1286, 1337

Offset

1,2

Links

Table of n, a(n) for n=1..51.

Formula

Empirical g.f.: x^2*(x^16-2*x^15+x^14+x^4-2*x^2-x-2) / ((x-1)^3*(x+1)*(x^2+1)). - Colin Barker, Aug 16 2014

a(n) = floor(A024380(n) / A024379(n+1)). - Sean A. Irvine, Jul 06 2019

Crossrefs

Cf. A024379, A024380.

Sequence in context: A135042 A109666 A215098 * A125622 A080551 A179207

Adjacent sequences: A024387 A024388 A024389 * A024391 A024392 A024393

Keyword

nonn

Author

Clark Kimberling

Extensions

More terms from Sean A. Irvine, Jul 06 2019

Status

approved