A059880 Positions of negative terms in A059876.

8, 32, 33, 34, 35, 36, 64, 65, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 152, 160, 161, 256, 257, 258, 259, 260, 261, 262, 263, 264, 265, 266, 267, 268, 269, 270, 272, 273, 274, 275

Offset: 1

Author

Antti Karttunen, Feb 05 2001

Keywords

• nonn

Programs

Maple

negative_terms(A059876); negative_terms := proc(b) local a,i; a := []; for i from 1 to nops(b) do if(b[i] < 0) then a := [op(a),i]; fi; od; RETURN(a); end;

Mathematica

a[n_] := With[{s = Floor[Log[2, n]]}, (-1)^(n+1) + Sum[(-1)^(Floor[n/2^i] + 1)*Prime[i], {i, 1, s}] + If[1 == n, 1, Mod[s + 1, 2]*Prime[s]]];
A059880 = Position[Array[a, 500], ?Negative] // Flatten (* _Jean-François Alcover, Mar 07 2016 *)