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

1,1

Comments

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

Links

Table of n, a(n) for n=1..37.

Example

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

Prog

(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

Crossrefs

Cf. A068991.

Sequence in context: A353023 A053327 A252537 * A248442 A043479 A002606

Adjacent sequences: A099005 A099006 A099007 * A099009 A099010 A099011

Keyword

nonn

Author

Benoit Cloitre, Nov 07 2004

Extensions

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

Status

approved