A230045 Palindromic primes with strictly increasing sum of digits.

2, 3, 5, 7, 181, 191, 373, 383, 727, 757, 787, 797, 17971, 19891, 19991, 76667, 77977, 78887, 79997, 1987891, 1988891, 1998991, 3799973, 3899983, 3998993, 7897987, 7996997, 9888889, 9889889, 9989899, 199999991, 768989867, 779969977, 779999977, 798989897

Offset: 1

Author

Shyam Sunder Gupta, Oct 06 2013

Keywords

• nonn
• base

Comments

a(1)=2; a(n+1) is the smallest palindromic prime with sum of digits > sum of digits of a(n).

Examples

			a(6) = 191, sum of digits is 11; a(7) = 373, sum of digits is 13 and 13 > 11.
		

Links

• Shyam Sunder Gupta, Table of n, a(n) for n = 1..63

Crossrefs

Cf. A002385, A061248.

Programs

Mathematica

a = {}; t = 0; Do[z = n*10^(IntegerLength[n] - 1) + FromDigits@Rest@Reverse@IntegerDigits[n]; If[PrimeQ[z], s = Apply[Plus, IntegerDigits[z]]; If[s > t, t = s; AppendTo[a, z]]], {n, 10^5}]; a