A082436 Palindromic primes with middle digit 1.

313, 919, 18181, 30103, 35153, 38183, 93139, 1201021, 1221221, 1281821, 1311131, 1371731, 1411141, 1461641, 1551551, 1611161, 1761671, 1831381, 1851581, 1881881, 1941491, 1951591, 1981891, 3001003, 3091903, 3181813, 3211123, 3241423

Offset

1,1

Links

David A. Corneth, Table of n, a(n) for n = 1..32860

Mathematica

Select[Prime[Range[250000]], OddQ[IntegerLength[#]]&& PalindromeQ[#] && IntegerDigits[ #][[(IntegerLength[#]+1)/2]]==1&](* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Dec 31 2018 *)

Prog

(Magma) [ p: p in PrimesUpTo(200000000) | IsOdd(d) and D[(d+1) div 2] eq 1 and D eq Reverse(D) where d is #D where D is Intseq(p) ]; // Vincenzo Librandi, Apr 12 2011
(PARI) first(n) = {my(res = List(), t = 0); forstep(i = 1, oo, 10, c = A002113(i); if(#digits(c) % 2 == 1 && isprime(c), print1(c", "); t++; listput(res, c); if(t == n, return(res))))} \\ David A. Corneth, Dec 31 2018

Crossrefs

Cf. A002385.

Sequence in context: A090514 A068681 A341802 * A108845 A348170 A340464

Adjacent sequences: A082433 A082434 A082435 * A082437 A082438 A082439

Keyword

nonn,easy,less,base

Author

Lekraj Beedassy, Apr 25 2003

Extensions

a(22) from Vincenzo Librandi, Apr 12 2011

Status

approved