cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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

Original entry on oeis.org

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

Views

Author

Zak Seidov, Jun 19 2015

Keywords

Crossrefs

Programs

  • 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

Extensions

More terms from Alois P. Heinz, Jun 19 2015