A231279 a(n) = Jacobsthal(n^2), where Jacobsthal(n) = A001045(n), for n>=1.
1, 5, 171, 21845, 11184811, 22906492245, 187649984473771, 6148914691236517205, 805950546409752783137451, 422550200076076467165567735125, 886151997189943915269204706853563051, 7433581732843541047178572757549453835326805
Offset: 1
Keywords
Programs
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PARI
{a(n)=(2^(n^2)-(-1)^n)/3} for(n=1,15,print1(a(n),", "))
Formula
a(n) = (2^(n^2) - (-1)^n) / 3.
One-third the logarithmic derivative of A211892.