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Start with 2, then successively subtract the primes 3, 5, 7, ...
1

%I #17 Feb 23 2017 23:06:16

%S 2,-1,-6,-13,-24,-37,-54,-73,-96,-125,-156,-193,-234,-277,-324,-377,

%T -436,-497,-564,-635,-708,-787,-870,-959,-1056,-1157,-1260,-1367,

%U -1476,-1589,-1716,-1847,-1984,-2123,-2272,-2423,-2580,-2743,-2910

%N Start with 2, then successively subtract the primes 3, 5, 7, ...

%F a(n) = A007504(n+1) - 2*A071148(n-1).

%e a(1) = 2 - 3 = -1;

%e a(2) = 2 - 3 - 5 = -6.

%t FoldList[#1 - #2 &, 2, Prime@ Range[2, 39]] (* _Michael De Vlieger_, Feb 12 2017 *)

%o (Python) from sympy import prime, isprime

%o sub=2

%o print(sub, end=", ")

%o for i in range (3, 200, 2):

%o if (isprime(i)==True):

%o sub=sub-i

%o print(sub, end=", ")

%o (PARI) lista(nn) = {s = prime(1); print1(s, ", "); for (n=2, nn, s -= prime(n); print1(s, ", "););} \\ _Michel Marcus_, Feb 12 2017

%Y Cf. A007504, A071148, A000040.

%K sign

%O 1,1

%A _Frederic Isenmann_, Feb 12 2017