A024378 a(n) = 2nd elementary symmetric function of the first n+1 positive integers congruent to 1 mod 4.

5, 59, 254, 730, 1675, 3325, 5964, 9924, 15585, 23375, 33770, 47294, 64519, 86065, 112600, 144840, 183549, 229539, 283670, 346850, 420035, 504229, 600484, 709900, 833625, 972855, 1128834, 1302854, 1496255, 1710425, 1946800, 2206864, 2492149

Offset: 1

Author

Clark Kimberling

Keywords

• nonn
• easy

Links

• Index entries for linear recurrences with constant coefficients, signature (5,-10,10,-5,1).

Programs

Maple

A024378:=n->n*(n+1)*(12*n^2+8*n-5)/6: seq(A024378(n), n=1..50); # Wesley Ivan Hurt, Apr 27 2017

Formula

a(n) = n*(n+1)*(12*n^2+8*n-5)/6.

G.f.: -x*(5+34*x+9*x^2) / (x-1)^5. - R. J. Mathar, Oct 08 2011