A230046 Palindromic primes with nondecreasing sum of digits.

2, 3, 5, 7, 151, 181, 191, 353, 373, 383, 727, 757, 787, 797, 17971, 19891, 19991, 38783, 74747, 75557, 76367, 76667, 77477, 77977, 78787, 78887, 79697, 79997, 1879781, 1895981, 1969691, 1987891, 1988891, 1998991, 3799973, 3899983, 3997993, 3998993, 7696967

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).

Links

• Shyam Sunder Gupta, Table of n, a(n) for n = 1..157

Crossrefs

Cf. A002385, A067954.

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