A127042 - OEIS

A127042

Primes p such that denominator of Sum_{k=1..p-1} 1/k^2 is a square.

2, 3, 5, 7, 17, 19, 29, 31, 37, 41, 97, 127, 131, 211, 223, 227, 229, 233, 239, 241, 439, 443, 449, 457, 461, 463, 727, 733, 739, 743, 751, 757, 761, 769, 773, 863, 877, 881, 883, 887, 967, 971, 977, 983, 991, 997, 1009, 1013, 1187, 1193, 1201, 1901, 1907, 1913, 1931, 1933

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

MATHEMATICA

a = {}; Do[If[Sqrt[Denominator[Sum[1/x^2, {x, 1, Prime[x] - 1}]]] == Floor[Sqrt[Denominator[Sum[1/x^2, {x, 1, Prime[x] - 1}]]]], AppendTo[a, Prime[x]]], {x, 1, 50}]; a

CROSSREFS

Cf. A061002, A034602, A127029.

Sequence in context: A113029 A090432 A301918 * A069802 A067954 A061248

Adjacent sequences: A127039 A127040 A127041 * A127043 A127044 A127045

KEYWORD

nonn

AUTHOR

Artur Jasinski, Jan 03 2007

EXTENSIONS

More terms from Franklin T. Adams-Watters, Jan 21 2012

STATUS

approved