A180458 Largest palindromic number <= n-th-prime.

2, 3, 5, 7, 11, 11, 11, 11, 22, 22, 22, 33, 33, 33, 44, 44, 55, 55, 66, 66, 66, 77, 77, 88, 88, 101, 101, 101, 101, 111, 121, 131, 131, 131, 141, 151, 151, 161, 161, 171, 171, 181, 191, 191, 191, 191, 202, 222, 222, 222, 232, 232, 232, 242, 252, 262, 262, 262, 272

Offset: 1

Author

Giovanni Teofilatto, Sep 06 2010

Keywords

• base
• nonn

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000040, A261423.

Programs

Maple

# given lists Primes of primes and Palis of palindromes, with Palis[-1] > Primes[-1]
m:= 1; A:= 'A':
for n from 1 to nops(Primes) do
  while m < nops(Palis) and Palis[m+1] <= Primes[n] do m:= m+1 od:
  A[n]:= Palis[m]
od:
seq(A[i],i=1..nops(Primes)); # Robert Israel, Apr 26 2016

Mathematica

lpn[n_]:=Module[{k=0},While[!PalindromeQ[n-k],k++];n-k]; Table[lpn[n],{n,Prime[Range[60]]}] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Dec 18 2020 *)

Extensions

Corrected by Robert Israel, Apr 26 2016