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A082436 Palindromic primes with middle digit 1. 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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
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
KEYWORD
nonn,easy,less,base
AUTHOR
Lekraj Beedassy, Apr 25 2003
EXTENSIONS
a(22) from Vincenzo Librandi, Apr 12 2011
STATUS
approved

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Last modified July 20 18:09 EDT 2024. Contains 374459 sequences. (Running on oeis4.)