A099008 Numbers n such that the denominator of the 2n-th Bernoulli number is divisible by n but sum_{d|n} sigma(d)/phi(d) is not an integer.

546, 903, 1806, 2730, 6162, 6510, 9030, 10230, 12090, 12246, 12810, 15834, 20130, 20670, 23478, 23790, 28938, 30030, 30810, 43134, 44310, 52374, 56730, 61230, 71610, 79170, 84630, 85722, 88410, 99330, 109230, 117390, 132990, 140910, 144690, 154770, 164010

Offset: 1

Author

Benoit Cloitre, Nov 07 2004

Keywords

• nonn

Comments

Intersection of A106741 and complement of A068991. - Michel Marcus, Dec 07 2013

Examples

			The denominator of the 1806th Bernoulli number is 1806 and Sum_{d|1806} sigma(d)/phi(d) = 172/3 is not an integer.
		

Crossrefs

Cf. A068991.

Programs

PARI

lista() = {v = readvec("b106741.txt"); for (i=1, #v, vi = v[i]; if (denominator(sumdiv(vi, d, sigma(d)/eulerphi(d))) != 1, print1(vi, ", ")));} \\ Michel Marcus, Dec 07 2013

Extensions

Extended using b-file from A106741 by Michel Marcus, Dec 07 2013