A259144 Number of n-digit primes whose sum of digits is 7.

1, 2, 7, 20, 28, 58, 95, 154, 226, 278, 403, 570, 734, 949, 1200, 1515, 1931, 2328, 2908, 3529, 4196, 5034, 5800, 6870, 7871, 9132, 10574, 12359, 14005, 15871, 17924, 20231, 22505, 25903, 28800, 31532, 34830, 38479, 43334, 48847, 52769, 57173, 61545, 67774, 75186

Offset

1,2

Links

Giovanni Resta, Table of n, a(n) for n = 1..100

Prog

(PARI) a(n)=n--; my(A, B, C, D); sum(a=0, n, A=10^n+10^a+1; sum(b=a, n, B=A+10^b; sum(c=b, n, C=B+10^c; sum(d=c, n, D=C+10^d; sum(e=d, n, isprime(D+10^e)))))) \\ Charles R Greathouse IV, Jun 19 2015

Crossrefs

Cf. A007953, A052221, A062337.

Sequence in context: A182655 A356396 A136907 * A090145 A244307 A368881

Adjacent sequences: A259141 A259142 A259143 * A259145 A259146 A259147

Keyword

nonn,base

Author

Zak Seidov, Jun 19 2015

Extensions

More terms from Alois P. Heinz, Jun 19 2015

Status

approved