OFFSET
1,1
LINKS
Eric Weisstein's World of Mathematics, Harmonic Number.
EXAMPLE
A027612(n) begins {1, 5, 13, 77, 87, 223, 481, 4609, 4861, ...}.
Thus a(1) = 5, a(2) = 13, a(3) = 223, a(4) = 4861.
MATHEMATICA
s=1; Do[s=s+1/(n+1); f=Numerator[(n+1)*(s-1)]; If[PrimeQ[f], Print[{n, f}]], {n, 1, 1942}]
PROG
(PARI) lista(nn) = {for (n=1, nn, if (isprime(p=numerator(sum(k=1, n, k/(n-k+1)))), print1(p, ", ")); ); } \\ Michel Marcus, Jul 14 2018
CROSSREFS
A027612(n) are the numerators of second order harmonic numbers H(n, (2)).
KEYWORD
nonn
AUTHOR
Alexander Adamchuk, Nov 11 2006
EXTENSIONS
a(12) from, and crossrefs edited by Michel Marcus, Jul 14 2018
STATUS
approved