A119723 Numerator of Sum[ (-1)^(k-1) * 1/(Prime[k]-1)^2, {k,1,n}].

1, 3, 13, 113, 2861, 709, 45601, 408809, 49595489, 2426258561, 485934733, 485460413, 2429223061, 2427480661, 1284905668069, 217047437215261, 182605590283392901, 36508279615059377, 36518889897389297

Offset

1,2

Links

Table of n, a(n) for n=1..19.

Eric Weisstein's World of Mathematics, Prime Sums.

Formula

a(n) = numerator[ Sum[ (-1)^(k-1) * 1/(Prime[k]-1)^2, {k,1,n}]].

Mathematica

Numerator[Table[Sum[(-1)^(i-1)*1/(Prime[i]-1)^2, {i, 1, n}], {n, 1, 30}]]

Crossrefs

Cf. A119686, A006093, A000040, A086242.

Sequence in context: A360187 A053583 A077713 * A093011 A262147 A364327

Adjacent sequences: A119720 A119721 A119722 * A119724 A119725 A119726

Keyword

frac,nonn

Author

Alexander Adamchuk, Jun 13 2006

Status

approved