A065537 a(n) is smallest prime > 10*a(n-1), a(1) = 7.

7, 71, 719, 7193, 71933, 719333, 7193357, 71933597, 719335993, 7193359933, 71933599363, 719335993631, 7193359936331, 71933599363319, 719335993633291, 7193359936332919, 71933599363329217, 719335993633292261

Offset: 1

Author

Robert G. Wilson v, Nov 28 2001

Keywords

• nonn

Links

• Harry J. Smith, Table of n, a(n) for n = 1..100

Crossrefs

Cf. A065122, A048552.

Programs

Mathematica

NextPrim[n_Integer] := Block[ {k = n + 1}, While[ !PrimeQ[k], k++ ]; Return[k]]; a[1] = 7; a[n_] := NextPrim[ 10*a[n - 1]]; Table[ a[n], {n, 1, 20} ]

PARI

{ for (n=1, 100, if (n>1, a=nextprime(10*a), a=7); write("b065537.txt", n, " ", a) ) } \\ Harry J. Smith, Oct 21 2009