A242833 Primes formed by the initial digits of the decimal expansion of 1/19, starting at the first nonzero digit in the expansion.

5, 52631, 5263157894736842105263157, 52631578947368421052631578947368421052631578947368421052631

Offset: 1

Author

Felix Fröhlich, May 23 2014

Keywords

• base
• nonn

Comments

a(5) has 95 digits and a(6) has 907 digits. - Michel Marcus, May 27 2014

Links

• Jon E. Schoenfield, Table of n, a(n) for n = 1..6

Crossrefs

Cf. A021023.

Corresponding sequences for 1/k: A242824 (k=7), A093676 (k=12), A242826 (k=13), A242827(k=14), A242828 (k=17).

Programs

PARI

lista(nn) = {v = [5,2,6,3,1,5,7,8,9,4,7,3,6,8,4,2,1,0]; n = 0; for (i=0, nn, n = 10*n+ v[(i % 18)+1]; if (ispseudoprime(n), print1(n, ", ")););} \\ Michel Marcus, May 27 2014