A157512 Partial sums of A157502.

2, 8, 16, 26, 38, 52, 70, 90, 112, 136, 162, 190, 220, 252, 286, 324, 364, 406, 450, 496, 544, 594, 646, 700, 756, 814, 874, 936, 1002, 1070, 1140, 1212, 1286, 1362, 1440, 1520, 1602, 1686, 1772, 1860, 1950, 2042, 2136, 2232, 2330, 2432, 2536

Offset: 1

Author

Gerald Hillier, Mar 02 2009

Keywords

• nonn

Examples

			a(4) = 2 + 6 + 8 + 10 = 26.
		

Crossrefs

Cf. A157502.

Programs

PARI

lista(nn) = {s = 0; forstep (i = 2, nn, 2, if (! issquare(i), s+=i; print1(s, ", ");););} \\ Michel Marcus, Aug 26 2013

Formula

Set R(n) = floor(A157502(n)/2) and S(n) = floor(sqrt(A157502(n))/2); then a(n) = R(n)*(R(n) + 1) - (4*S(n)^3 + 6*S(n)^2 + 2*S(n))/3.

Extensions

More terms from Michel Marcus, Aug 26 2013