A356061 - OEIS

A356061

Numbers whose sum of digits is a refactorable number.

1, 2, 8, 9, 10, 11, 17, 18, 20, 26, 27, 35, 36, 39, 44, 45, 48, 53, 54, 57, 62, 63, 66, 71, 72, 75, 80, 81, 84, 90, 93, 99, 100, 101, 107, 108, 110, 116, 117, 125, 126, 129, 134, 135, 138, 143, 144, 147, 152, 153, 156, 161, 162, 165, 170, 171, 174, 180, 183, 189, 192, 198, 200

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

Also numbers k such that A007953(k) = c * A000005(A007953(k)); c >= 1 is a positive integer. For c = 1 see A356520.

LINKS

Table of n, a(n) for n=1..63.

EXAMPLE

k = 17; A007953(17) = 2 * A000005(A007953(17)), thus k = 17 is in the sequence.

MAPLE

filter:= proc(n) local s; s:= convert(convert(n, base, 10), `+`); s mod numtheory:-tau(s) = 0 end proc:

select(filter, [$1..200]); # Robert Israel, Aug 10 2022