A333921 a(n) is the least k such that the decimal representation of n appears as a substring in the concatenation of 0, 1, ..., k.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 2, 13, 14, 15, 16, 17, 18, 19, 20, 13, 22, 3, 24, 25, 26, 27, 28, 29, 30, 14, 24, 33, 4, 35, 36, 37, 38, 39, 40, 15, 25, 35, 44, 5, 46, 47, 48, 49, 50, 16, 26, 36, 46, 55, 6, 57, 58, 59, 60, 17, 27, 37, 47, 57, 66, 7, 68

Offset

0,3

Comments

Every nonnegative integer appears finitely many times in this sequence.

Links

Rémy Sigrist, Table of n, a(n) for n = 0..10000

Formula

a(n) <= n with equality iff n = 0 or n belongs to A131881.

a(A007908(n)) = n for any n > 0.

Prog

(PARI) a(n, base=10) = { my (w=base^#digits(n, base), m=0); for (k=0, oo, my (d=if (k, digits(k, base), [0])); for (i=1, #d, m=(base*m+d[i])%w; if (m==n, return (k)))) }

Crossrefs

Cf. A007908, A116700, A131881, A333920 (binary variant).

Sequence in context: A056961 A297239 A043271 * A278063 A375931 A373231

Adjacent sequences: A333918 A333919 A333920 * A333922 A333923 A333924

Keyword

nonn,base

Author

Rémy Sigrist, Apr 10 2020

Status

approved