A077131 Sum of odd-indexed primes.

2, 7, 18, 35, 58, 89, 130, 177, 236, 303, 376, 459, 556, 659, 768, 895, 1032, 1181, 1338, 1505, 1684, 1875, 2072, 2283, 2510, 2743, 2984, 3241, 3510, 3787, 4070, 4377, 4690, 5021, 5368, 5721, 6088, 6467, 6856, 7257, 7676, 8107, 8546, 8995, 9456, 9923, 10410

Offset: 1

Author

Jon Perry, Nov 29 2002

Keywords

• nonn

Comments

Partial sums of A031368. - Michel Marcus, Oct 27 2015

Examples

			p_1=2, p_2=3 and p_3=5, therefore a(2) = p_1 + p_3 = 2 + 5 = 7.
		

Links

• Paolo Xausa, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A031368, A077126.

Programs

Mathematica

A077131list[nmax_]:=Accumulate[Prime[Range[1,2nmax,2]]];A077131list[100] (* Paolo Xausa, Aug 28 2023 *)
Accumulate[Prime[Range[1,101,2]]] (* Harvey P. Dale, Nov 08 2024 *)

PARI

a(n)=if(n<1,0,sum(k=1,n, prime(2*k-1)))

Formula

a(n) ~ n^2 log n. - Charles R Greathouse IV, Jan 09 2025