A345672 a(n) is the least m such that the decimal expansion of n appears in the concatenation of m, ..., m+k for some k >= 0 and Sum_{i = m..m+k-1} A055642(i) < A055642(n) <= Sum_{i = m..m+k} A055642(i).

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 1, 13, 14, 15, 16, 17, 18, 19, 20, 12, 22, 2, 24, 25, 26, 27, 28, 29, 30, 13, 23, 33, 3, 35, 36, 37, 38, 39, 40, 14, 24, 34, 44, 4, 46, 47, 48, 49, 50, 15, 25, 35, 45, 55, 5, 57, 58, 59, 60, 16, 26, 36, 46, 56, 66, 6, 68

Offset: 0

Author

Rémy Sigrist, Jun 22 2021

Keywords

• nonn
• base

Comments

This sequence is similar to A055642; here we consider decimal expansions, there binary expansions.

Examples

			For n = 21:
- the decimal expansion of 21 first appears in the concatenation of 12 and 13,
- so a(21) = 12.
		

Links

• Rémy Sigrist, PARI program for A345672

Crossrefs

Cf. A007376, A055642, A083653 (binary analog), A252043.

Programs

PARI

See Links section.

Formula

a(n) <= n.

a(n) = 1 iff n belongs to A252043.