A056544 Smallest palindrome containing the digits of n as a subsequence.

1, 2, 3, 4, 5, 6, 7, 8, 9, 101, 11, 121, 131, 141, 151, 161, 171, 181, 191, 202, 121, 22, 232, 242, 252, 262, 272, 282, 292, 303, 131, 232, 33, 343, 353, 363, 373, 383, 393, 404, 141, 242, 343, 44, 454, 464, 474, 484, 494, 505, 151, 252, 353, 454, 55, 565, 575

Offset: 1

Author

Joseph L. Pe, Feb 10 2002

Keywords

• base
• easy
• nonn

Examples

			The smallest palindrome containing 21 as a subsequence is 121. So a(21) = 121.
		

Links

• Rémy Sigrist, Table of n, a(n) for n = 1..10000
• Rémy Sigrist, PARI program for A056544

Crossrefs

Cf. A002113, A082216, A145800 (binary variant).

Programs

Mathematica

Do[k = 1; While[ StringPosition[ ToString[k], ToString[n]] == {} || ToString[k] != StringReverse[ ToString[k]], k++ ]; Print[k], {n, 1, 70} ]

PARI

See Links section.

Formula

a(A002113(n)) = A002113(n). - Chai Wah Wu, Apr 13 2021

Extensions

Edited and extended by Robert G. Wilson v, Feb 12 2002