OFFSET
1,2
COMMENTS
LINKS
Metin Sariyar, Table of n, a(n) for n = 1..500
FORMULA
a(n) = denominator(-(2^n*LerchPhi(2,1,n+1) + Pi*i/2 + HarmonicNumber(n))). - G. C. Greubel, Dec 28 2019
MAPLE
seq(denom(add((2^(k-1)-1)/k, k = 1..n)), n = 1..45); # G. C. Greubel, Dec 28 2019
MATHEMATICA
Denominator@Accumulate@Array[(2^(#-1) -1)/# &, 45]
Table[Denominator[-(2^n*LerchPhi[2, 1, n+1] +Pi*I/2 +HarmonicNumber[n])], {n, 45}] (* G. C. Greubel, Dec 28 2019 *)
PROG
(PARI) a(n) = denominator(sum(k=1, n, (2^(k-1)-1)/k)); \\ Michel Marcus, Dec 28 2019
(Magma) [Denominator( &+[(2^(k-1)-1)/k: k in [1..n]] ): n in [1..45]]; // G. C. Greubel, Dec 28 2019
(Sage) [denominator( sum((2^(k-1)-1)/k for k in (1..n)) ) for n in (1..45)] # G. C. Greubel, Dec 28 2019
CROSSREFS
KEYWORD
nonn,frac
AUTHOR
Amiram Eldar and Thomas Ordowski, Dec 28 2019
STATUS
approved