A139232 Second differences of Mersenne primes A000668.

20, 72, 7968, 114816, 270336, 2146566144, 2305843004919250944, 618970015031004121169657856, 162258038889176383854312324857856, 170140858942534543324603210697313091584

Offset: 1

Author

Omar E. Pol, Apr 19 2008

Keywords

• nonn

Comments

Second differences of even superperfect numbers, multiplied by 2 (see A139236).

Links

• G. C. Greubel, Table of n, a(n) for n = 1..16

Crossrefs

Cf. A000668, A019279, A061652, A139228, A139229, A139230, A139231, A139233, A139234, A139235, A139236, A139237.

Programs

Mathematica

A000668 := Select[2^Range[1000] - 1, PrimeQ]; Table[A000668[[n + 2]] - 2*A000668[[n + 1]] + A000668[[n]], {n, 1, 6}] (* G. C. Greubel, Oct 03 2017 *)
Differences[2^MersennePrimeExponent[Range[14]]-1,2] (* Paolo Xausa, Oct 20 2023 *)

Formula

a(n) = A139236(n)*2.

Extensions

Terms a(7) - a(10) added by G. C. Greubel, Oct 03 2017