A353023 Positive integers k with the property that they cannot be converted to a multiple of 11 by changing at most a single decimal digit.

545, 27272, 1818181, 636363636, 90909090909, 181818181818, 272727272727, 363636363636, 454545454545, 545454545454, 636363636363, 727272727272, 818181818181, 909090909090, 363636363636363, 81818181818181818, 7272727272727272727, 454545454545454545454

Offset: 1

Author

Ben Weiss, May 15 2022

Keywords

• base
• nonn

Comments

This sequence was inspired by a puzzle from David K. Butler.

Links

• Ben Weiss, Multiples of 11

Crossrefs

Cf. A008593 (multiples of 11).

Formula

a(n) = a(n - 18) * 10^22 + (a(n - 18) mod 100) * 101010101010101010101.