OFFSET
1,1
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
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 *)
CROSSREFS
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