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A139232
Second differences of Mersenne primes A000668.
11
20, 72, 7968, 114816, 270336, 2146566144, 2305843004919250944, 618970015031004121169657856, 162258038889176383854312324857856, 170140858942534543324603210697313091584
OFFSET
1,1
COMMENTS
Second differences of even superperfect numbers, multiplied by 2 (see A139236).
LINKS
FORMULA
a(n) = A139236(n)*2.
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 *)
KEYWORD
nonn
AUTHOR
Omar E. Pol, Apr 19 2008
EXTENSIONS
Terms a(7) - a(10) added by G. C. Greubel, Oct 03 2017
STATUS
approved