OFFSET
1,1
COMMENTS
Subsequence of A127061. - Max Alekseyev, Feb 08 2007
FORMULA
MATHEMATICA
pdenQ[n_]:=Module[{c=Denominator[Table[Sum[1/k^i, {k, n-1}], {i, 2, 4}]]}, AllTrue[{ Surd[c[[1]], 2], Surd[c[[2]], 3], Surd[c[[3]], 4]}, IntegerQ]]; Select[Prime[Range[12000]], pdenQ] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Jun 06 2015 *)
PROG
(PARI) lista(nn) = {forprime(p = 2, nn, if (issquare(denominator(sum(k=1, p-1, 1/k^2))) && ispower(denominator(sum(k=1, p-1, 1/k^3)), 3) && ispower(denominator(sum(k=1, p-1, 1/k^4)), 4), print1(p, ", ")); ); } \\ Michel Marcus, Nov 05 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Artur Jasinski, Jan 04 2007
EXTENSIONS
More terms from Max Alekseyev, Feb 08 2007
STATUS
approved