A077131 - OEIS

%I #16 Aug 28 2023 16:46:36

%S 2,7,18,35,58,89,130,177,236,303,376,459,556,659,768,895,1032,1181,

%T 1338,1505,1684,1875,2072,2283,2510,2743,2984,3241,3510,3787,4070,

%U 4377,4690,5021,5368,5721,6088,6467,6856,7257,7676,8107,8546,8995,9456,9923,10410

%N Sum of odd-indexed primes.

%C Partial sums of A031368. - _Michel Marcus_, Oct 27 2015

%H Paolo Xausa, <a href="/A077131/b077131.txt">Table of n, a(n) for n = 1..10000</a>

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

%t A077131list[nmax_]:=Accumulate[Prime[Range[1,2nmax,2]]];A077131list[100] (* _Paolo Xausa_, Aug 28 2023 *)

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

%Y Cf. A031368, A077126.

%K nonn

%O 1,1

%A _Jon Perry_, Nov 29 2002