A069798 Primes whose digit reversal is a nontrivial power.

23, 61, 163, 487, 521, 691, 821, 1297, 1861, 4201, 4441, 4483, 5209, 5227, 9049, 9631, 12391, 14437, 16141, 16987, 61483, 63211, 65707, 65899, 67057, 69481, 92767, 94273, 96979, 106303, 108061, 123031, 123373, 125329, 127291, 129643, 142771, 146857, 148249

Offset

1,1

Links

Chai Wah Wu, Table of n, a(n) for n = 1..14573

Example

691 is in the sequence because it is prime and its reversal, 196, is a power (greater than one) of 14.

Mathematica

f[n_] := Block[{a, p = ToExpression[ StringReverse[ ToString[ Prime[n]]]]}, Log[ Apply[ Times, Transpose[ FactorInteger[p]][[1]]], p]]; Prime[ Select[ Range[10^5], IntegerQ[ f[ # ]] && f[ # ] > 1 &]]

Prog

(PARI) lista(nn) = {forprime(p=2, nn, if (ispower(subst(Polrev(digits(p)), x, 10)), print1(p, ", ")); ); } \\ Michel Marcus, Jun 03 2016

Crossrefs

Cf. A007488, A067194.

Sequence in context: A215166 A141870 A115685 * A067194 A355984 A355985

Adjacent sequences: A069795 A069796 A069797 * A069799 A069800 A069801

Keyword

base,nonn

Author

Amarnath Murthy, Apr 09 2002

Extensions

Edited, corrected and extended by Robert G. Wilson v, Apr 15 2002

Missing terms a(4), a(24), and a(26) added by Chai Wah Wu, Jun 02 2016

Status

approved