A196225 Smallest number k such that sigma(tau(k)) = n, or 0 if there is no such k.

1, 0, 2, 4, 0, 16, 6, 64, 0, 0, 0, 12, 36, 4096, 24, 0, 0, 48, 0, 262144, 0, 0, 0, 192, 0, 0, 0, 60, 0, 268435456, 120, 576, 0, 0, 0, 3072, 0, 68719476736, 180, 900, 0, 240, 0, 4398046511104, 0, 0, 0, 9216, 0, 0, 0, 0, 0, 196608, 0, 960, 46656, 0, 0, 360, 0, 1152921504606846976

Offset

1,3

Comments

Smallest number k such that A062069(k) = A000203(A000005(k)) = n, or 0 if there is no such k.

Links

Table of n, a(n) for n=1..62.

Formula

a(n)=0 iff A051444(n) = 0.

Example

a(6) = 16 because number 16 is the smallest number k such that sigma(tau(k)) = 6; (tau(16)=5, sigma(5)=6).

Crossrefs

Cf. A062069 (sigma(tau(n))), A000203(sigma(n)), A000005(tau(n)).

Sequence in context: A203850 A106603 A059057 * A127511 A321956 A173315

Adjacent sequences: A196222 A196223 A196224 * A196226 A196227 A196228

Keyword

nonn

Author

Jaroslav Krizek, Jan 02 2013

Status

approved