A032596 Second of three consecutive palindromes all of which are prime.

1879781, 1880881, 1969691, 3590953, 7820287, 108494801, 159191951, 160707061, 175101571, 187101781, 316696613, 319404913, 725595527, 728898827, 731909137, 904090409, 921202129, 930505039, 987202789, 987494789, 10456965401, 10745054701

Offset

1,1

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

P. De Geest, World!Of Palindromic Primes

Prog

(PARI) nxt(n)=my(d=digits(n)); i=(#d+1)\2; while(i&&d[i]==9, d[i]=0; d[#d+1-i]=0; i--); if(i, d[i]++; d[#d+1-i]=d[i], d=vector(#d+1); d[1]=d[#d]=1); sum(i=1, #d, 10^(#d-i)*d[i]) \\ From David A. Corneth at A002113
list(lim)=my(v=List(), p=1, q=2, r=3); while(q<=lim\=1, if(isprime(r), if(isprime(q), if(isprime(p), listput(v, q)); p=q; q=r; r=nxt(r), q=nxt(p=r); r=nxt(q)), q=nxt(p=nxt(r)); r=nxt(q))); Vec(v) \\ Charles R Greathouse IV, Aug 11 2021

Crossrefs

Cf. A002385, A032595, A032597.

Sequence in context: A064820 A032595 A230806 * A032597 A203794 A204672

Adjacent sequences: A032593 A032594 A032595 * A032597 A032598 A032599

Keyword

nonn,base

Author

Patrick De Geest, May 15 1998

Extensions

New name from Charles R Greathouse IV, Aug 11 2021

Status

approved