A181507 Primes such that the sum of squares of digits of all primes up to itself is a prime.

3, 11, 17, 37, 43, 151, 173, 191, 223, 233, 367, 401, 421, 433, 449, 457, 509, 787, 839, 1019, 1061, 1103, 1123, 1171, 1187, 1217, 1237, 1451, 1663, 1709, 1723, 1871, 1901, 1973, 2251, 2297, 2351, 2371, 2753, 3023, 3121, 3181, 3217, 3221, 3319, 3389, 3391

Offset

1,1

Comments

There are infinite twins: (3389,3391)-(8231,8233)-(18251,18253)-(23687,23689)-(26111,26113) .....

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Formula

A linear approximation for the sequence is a(n)=128.81n-3291.7

Example

a(5)=43 since sum of square of digits (2,3,5,7,...primes up to 43)=439 which is prime.

Mathematica

Prime/@Flatten[Position[Accumulate[Total/@(IntegerDigits[Prime[Range[ 500]]]^2)], _?PrimeQ]] (* Harvey P. Dale, May 24 2012 *)

Crossrefs

Cf. A000040

Sequence in context: A018520 A154933 A197225 * A154934 A302872 A023865

Adjacent sequences: A181504 A181505 A181506 * A181508 A181509 A181510

Keyword

nonn,base

Author

Carmine Suriano, Oct 25 2010

Status

approved