A225741 Primes p such that the sum of the squares of the digits of p plus p is the square of a prime.

71, 1997, 2707, 3407, 32647, 143509, 177131, 196073, 273433, 292517, 360977, 418447, 477341, 578789, 981769, 1066867, 1079269, 1125559, 1394539, 2024831, 2246851, 2679493, 3659401, 3736351, 4932637, 5148233, 5479939, 5726257, 5726321, 5755051, 7070093, 7091339, 7789289, 8082419

Offset

1,1

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..3016

Example

71 is a member since 71+(7^2+1^2)=11^2, 1997 is a member since 1997+(1^2+9^2+9^2+7^2)= 47^2.

Prog

(PARI) ssd(n)=my(d=digits(n)); sum(i=1, #d, d[i]^2)
is(n)=my(t); issquare(ssd(n)+n, &t) && isprime(t) && isprime(n) \\ Charles R Greathouse IV, Aug 13 2013

Crossrefs

Sequence in context: A198449 A093271 A201608 * A049295 A017787 A332665

Adjacent sequences: A225738 A225739 A225740 * A225742 A225743 A225744

Keyword

nonn,base,less

Author

Will Gosnell, Aug 13 2013

Extensions

a(5)-a(34) from Charles R Greathouse IV, Aug 13 2013

Status

approved