A074970 Number of steps to reach the first integer starting with sigma(n)/n and iterating the map x -> x*ceiling(x), or -1 if no integer is ever reached.

0, 1, 2, 2, 18, 0, 3, 2, 3, 3, 26, 1, 9, 3, 7, 3, 6, 3, 56, 10, 9, 15, 42, 2, 10, 3, 3, 0, 38, 17, 79, 3, 27, 16, 8, 8, 200, 76, 4, 3, 36, 2, 4, 15, 4, 51, 11, 2, 4, 6, 22, 42, 43, 5, 25, 2, 4, 103, 37, 17, 18, 20, 8, 3, 22, 25, 225, 59, 6, 13, 20, 4, 182, 13, 8

Offset

1,3

Comments

a(p) = A073524(p) for primes p.

Links

Table of n, a(n) for n=1..75.

Example

a(26)=3 since (26+13+2+1)/26=21/13 -> 42/13 -> 168/13 -> 168.

Crossrefs

Cf. A000203, A009194, A073524.

Sequence in context: A222451 A000528 A260478 * A297794 A291765 A231123

Adjacent sequences: A074967 A074968 A074969 * A074971 A074972 A074973

Keyword

nonn

Author

Reinhard Zumkeller, Oct 05 2002

Extensions

a(20) corrected by and more terms from Jinyuan Wang, Jan 15 2022

Status

approved