A361336 Smallest decimal number containing n palindromic substrings (Version 2). See Comments for precise definition.

0, 10, 11, 100, 1002, 111, 1000, 10002, 10001, 1111, 10000, 100002, 100001, 1000012, 11111, 100000, 1000002, 1000001, 10000012, 10000010, 111111, 1000000, 10000002, 10000001, 100000012, 100000010, 110111111, 1111111, 10000000, 100000002, 100000001, 1000000012, 1000000010

Offset: 1

Author

N. J. A. Sloane, Apr 01 2023, based on postings to the Sequence Fans Mailing list by Eric Angelini, Mar 28 2023 (definition), and Giovanni Resta, Mar 28 2023 (terms)

Keywords

• nonn
• base

Comments

Suppose m has decimal expansion d_1 d_2 ... d_k. A palindromic substring here is any substring d_i, d_{i+1}, ..., d_j with 1 <= i <= j <= n which is palindromic. In this version d_i can be 0 even if j>i. For example, if m = 10^3 + 1 = 1001 there are six substrings: 1, 0, 0, 1, 00, and 1001. See A361335 for Version 1.

Links

• Giovanni Resta, Table of n, a(n) for n = 1..99

Crossrefs

Cf. A361335.