A158915 Least number k such that there is an m > k with sigma_n(k) = sigma_n(m).

2, 6, 6, 184926

Offset

0,1

Comments

It is easy to verify the first three terms using sequences A000005, A000203, and A001157. The first term of A131908 gives a(3). The a(4) term is greater than 10^8. Does a(n) exist for all n?

Links

Table of n, a(n) for n=0..3.

Example

sigma_0(2)=sigma_0(3); sigma_1(6)=sigma_1(12); sigma_2(6)=sigma_2(7); sigma_3(184926)=sigma_3(194315).

Crossrefs

Sequence in context: A279841 A219195 A212223 * A257478 A243523 A011044

Adjacent sequences: A158912 A158913 A158914 * A158916 A158917 A158918

Keyword

more,nonn

Author

T. D. Noe, Mar 30 2009

Status

approved