A131693 Numbers n such that S(n) = 0, where S(n) = (S(n-1) + A000040(n+1))*(-1)^n; S(0)=0, n >= 1.

10, 14, 18, 4290, 4392, 4434, 4440, 4456, 4480, 48596, 48620, 48744, 49540, 49544, 49722, 55058, 55078, 55200, 56466, 56474, 60110, 60128, 60462, 60750, 61328, 61486, 62114, 62758, 62770, 62974, 62992, 63022, 63076, 63094, 63272, 63802

Offset

1,1

Comments

Or, with A065091(odd primes), numbers n such that S(n) = 0, where S(n) = (S(n-1) + A065091(n))*(-1)^n; S(0)=0, n >= 1.

Links

Table of n, a(n) for n=1..36.

Example

S(9) = (..((0+3)*-1)+5)*1)+7)*-1)+11)*1)+13)*-1)+17)*1)+19)*-1)+23)*1)+29)*-1 = -31, S(10)=(-31 + 31)*1 = 0, hence 10 is a term.
S(13) = (..((0+3)*-1)+5)*1)+7)*-1)+11)*1)+13)*-1)+17)*1)+19)*-1)+23)*1)+29)*-1)+31)*1)+37)*-1)+41)*1)+43)*-1 = -47, S(14)=(-47 + 47)*1 = 0, hence 14 is a term.

Mathematica

S=0; a=0; Do[S=(S+Prime[n+1])*(-1)^n; If[S==0, a++; Print[a, " ", n]], {n, 1, 10^8, 1}]

Crossrefs

Cf. A131196, A131197, A130642, A130643, A065091, A000040.

Sequence in context: A055985 A190888 A157138 * A255532 A307516 A069900

Adjacent sequences: A131690 A131691 A131692 * A131694 A131695 A131696

Keyword

nonn

Author

Manuel Valdivia, Oct 03 2007

Status

approved