A100772 a(1) = 1; for n>1, a(n+1) is the least number such that there are a(n) palindromes between a(n) and a(n+1) with both ends excluded.

1, 3, 7, 56, 617, 58886, 495747595, 39580716961708594, 295807174575157636751575471708593, 19580717457515767633229292922435653422929292233676751575471708592

Offset: 1

Author

Amarnath Murthy, Nov 28 2004

Keywords

• base
• nonn

Examples

			a(3)= 7, a(4) = 56 as there are 7 palindromes between 7 and 56: (8,9,11,22,33,44,55).
		

Links

• Andrew Howroyd, Table of n, a(n) for n = 1..14

Crossrefs

Cf. A002113 (palindromes in base 10).

Programs

Mathematica

Nest[Append[#, Block[{k = 0}, Catch@ Do[Which[k == #[[-1]], Throw[i]; Break[], PalindromeQ@ i, k++, True, Nothing], {i, #[[-1]] + 1, Infinity}]]] &, {1}, 5] (* Michael De Vlieger, Jan 28 2020 *)

PARI

\\ Requires A002113.
a(n)={my(k=1, t=0); for(i=1, n, t=1+A002113(k); k += t + (t<10)); t} \\ Andrew Howroyd, Jan 27 2020

Extensions

a(5)-a(7) from Ray Chandler, Dec 10 2004

a(8) from Donovan Johnson, Dec 03 2009

Terms a(9) and beyond from Andrew Howroyd, Jan 27 2020