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A259144 Number of n-digit primes whose sum of digits is 7. 1
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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
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
Sequence in context: A182655 A356396 A136907 * A090145 A244307 A368881
KEYWORD
nonn,base
AUTHOR
Zak Seidov, Jun 19 2015
EXTENSIONS
More terms from Alois P. Heinz, Jun 19 2015
STATUS
approved

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Last modified May 22 13:22 EDT 2024. Contains 372755 sequences. (Running on oeis4.)