A119657 Denominator of BernoulliB[10p] divided by 66, where p=Prime[n].

5, 217, 1, 71, 23, 131, 1, 191, 47, 59, 311, 1, 83, 431, 1, 107, 1, 1, 1, 1, 1, 1, 167, 179, 971, 1, 1031, 1, 1091, 227, 1, 263, 1, 1, 1, 1511, 1571, 1, 1, 347, 359, 1811, 383, 1931, 1, 1, 2111

Offset: 1

Author

Alexander Adamchuk, Jul 28 2006

Keywords

• nonn

Comments

The only composite in this sequence is a(2) = 217 = 7*31. All other a(n) are equal to 1 (for n=3,7,12,15,17,18,19,20,21,22,26,28,31,33,34,35,38,39,45,46..) or prime: a(1) = 5, all other primes in a(n) belong to A068231[n]: Primes congruent to 11 (mod 12). It appears that every prime from A068231[n] except 11 shows up in a(n) just once.

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..500

Crossrefs

Cf. A068231, A119456, A051230, A051229, A002445.

Programs

Mathematica

Table[Denominator[BernoulliB[10Prime[n]]]/66,{n,1,47}]

Formula

a(n) = Denominator[BernoulliB[10Prime[n]]]/66.