A241246 Primes p such that the decimal expansion of its base 7 expansion converted to decimal is a square.

13, 19, 139, 313, 433, 571, 883, 1489, 3547, 10513, 11779, 14389, 20011, 25939, 27763, 30181, 32353, 42649, 44617, 45289, 46309, 47353, 48787, 55411, 65269, 65713, 96331, 111577, 120763, 129967, 151717, 157219, 201997, 216091, 281947, 292549, 322537, 339121, 373987, 397489, 420349, 432961, 460417, 475417, 478531, 506563, 582433, 591739, 599479, 753229, 778357, 857821, 861139, 887947, 968419, 1037089, 1062361, 1213651, 1246249

Offset

1,1

Comments

No terms are 0, 2, or 3 mod 7. - Charles R Greathouse IV, Apr 18 2014

Links

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

Example

{13,19,139,313,433,571,883,1489,3547,10513,11779}_10 =
{16,25,256,625,1156,1444,2401,4225,13225,42436,46225}_7 =
{4,5,16,25,34,38,49,65,115,206,215}^2_10.

Prog

(PARI) is(n)=issquare(subst(Pol(digits(n, 7)), 'x, 10)) && isprime(n) \\ Charles R Greathouse IV, Apr 18 2014
(PARI) for(n=4, 1e3, if(vecmax(v=digits(n^2))<7 && isprime(p= subst(Pol(v), 'x, 7)), print1(p", "))) \\ Charles R Greathouse IV, Apr 18 2014

Crossrefs

Cf. A090710, A065725.

Sequence in context: A180531 A271926 A090258 * A153266 A166664 A147393

Adjacent sequences: A241243 A241244 A241245 * A241247 A241248 A241249

Keyword

nonn,base

Author

Zak Seidov, Apr 18 2014

Status

approved