A293275 Exponent of highest power of 2 dividing the n-th (2,k)-perfect number A019278.

0, 1, 2, 3, 0, 4, 0, 3, 1, 2, 6, 2, 5, 3, 4, 4, 5, 3, 9, 6, 0, 6, 9, 2, 12, 9, 9, 4, 0, 9, 5, 8, 5, 1, 12, 6, 16, 12, 2, 7, 18, 8, 3, 4, 0, 10, 8, 5, 16, 2, 8, 16, 14, 10, 6, 1, 2, 8, 3, 18, 12, 8, 18, 11, 11, 4, 14, 9, 5, 10, 6, 11, 5, 5, 16, 7, 14, 12, 8, 13, 9, 18

Offset: 1

Author

Michel Marcus, Oct 10 2017

Keywords

• nonn

Links

• Michel Marcus, Table of n, a(n) for n = 1..130

Crossrefs

Cf. A007814, A019278, A205597 (when a(n) is zero).

Cf. A134665 (analog for multiperfect numbers).

Programs

PARI

lista(nn) = for (n=1, nn, if (denominator(sigma(sigma(n))/n) == 1, print1(valuation(n, 2), ", "));); \\ Michel Marcus, Oct 10 2017

Formula

a(n) = A007814(A019278(n)).