A230104 Numbers k such that m + (product of digits of m) is never equal to k.

1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 25, 27, 31, 33, 36, 37, 39, 43, 48, 49, 51, 52, 53, 57, 59, 61, 63, 64, 69, 71, 72, 73, 76, 77, 79, 82, 83, 84, 87, 91, 93, 96, 97, 99, 111, 113, 115, 117, 119, 121, 127, 131, 133, 136, 137, 139, 148, 149, 151, 153, 157, 159, 163, 164, 169, 171, 172, 173, 176, 177, 179, 182, 183

Offset

1,2

Comments

Numbers missing from A230099.

Links

Michael S. Branicky, Table of n, a(n) for n = 1..10000

Index entries for Colombian or self numbers and related sequences

Prog

(PARI) f(n) = if (n, n + vecprod(digits(n)), 0); \\ A230104
isok(m) = for(i=1, m, if (f(i) == m, return(0))); return(1); \\ Michel Marcus, Jan 09 2023
(Python)
from math import prod
def b(n): return n + prod(map(int, str(n)))
def aupto(n): return sorted(set(range(n+1)) - set(b(m) for m in range(n+1)))
print(aupto(183)) # Michael S. Branicky, Jan 09 2023

Crossrefs

Cf. A230099, A230103, A230105.

Sequence in context: A293167 A357377 A062505 * A093031 A305468 A143452

Adjacent sequences: A230101 A230102 A230103 * A230105 A230106 A230107

Keyword

nonn,base

Author

N. J. A. Sloane, Oct 13 2013

Status

approved