A333775 a(0) = 0; for n > 0, a(n) is the smallest positive integer not yet appearing in the sequence such that a(n-1) * a(n) contains as a substring either a(n-1) or a(n).

0, 1, 2, 6, 4, 10, 3, 5, 7, 11, 8, 16, 20, 21, 9, 22, 51, 12, 26, 24, 52, 76, 28, 46, 40, 31, 30, 41, 15, 50, 13, 25, 17, 69, 34, 42, 94, 100, 14, 82, 71, 60, 36, 38, 89, 55, 61, 35, 80, 56, 87, 33, 75, 29, 53, 101, 18, 66, 151, 32, 91, 43, 102, 19, 63, 137, 83, 96, 126, 44, 59, 27, 103

Offset: 0

Author

Scott R. Shannon, Apr 05 2020

Keywords

• nonn
• base

Examples

			a(1) = 1 as a(0) * a(1) = 0 * 1 = 0 which contains '0' as a substring.
a(4) = 4 as a(3) * a(4) = 6 * 4 = 24 which contains '4' as a substring.
a(18) = 26 as a(17) * a(18) = 12 * 26 = 312 which contains '12' as a substring.
		

Links

• Rémy Sigrist, Table of n, a(n) for n = 0..10000
• Rémy Sigrist, PARI program for A333775

Crossrefs

Cf. A333774, A333811, A332795, A332703.

Programs

PARI

See Links section.