A225079 Numbers n such that n^2 plus (sum of digits of n^2)^2 is prime.

1, 10, 11, 19, 31, 38, 43, 44, 50, 64, 85, 94, 95, 121, 131, 139, 142, 154, 158, 166, 175, 176, 179, 194, 206, 211, 212, 214, 226, 229, 233, 238, 256, 260, 265, 284, 286, 292, 295, 329, 340, 353, 362, 364, 365, 380, 397, 400, 418, 428, 449, 464, 467, 470, 491

Offset

1,2

Comments

There are fewer consecutive terms in the sequence (330 in the first 10000) than expected by chance (p~0.000000005, determined by bootstrap resampling).

Links

Christian N. K. Anderson, Table of n, a(n) for n = 1..10000

Example

467 is in this sequence because 467^2 = 218089, and 218089 + (2 + 1 + 8 + 0 + 8 + 9)^2 = 218873, which is prime.

Prog

(R) library(gmp); ya=rep(0, 100); cv=as.bigz(0); len=0
while(len<100) if(isprime((cv=cv+1)^2+digsum(cv^2)^2)) ya[(len=len+1)]=as.numeric(cv)

Crossrefs

Sequence in context: A037307 A341820 A296862 * A214790 A191221 A216996

Adjacent sequences: A225076 A225077 A225078 * A225080 A225081 A225082

Keyword

nonn,base

Author

Kevin L. Schwartz and Christian N. K. Anderson, Apr 26 2013

Status

approved