A110781 Number of digits in A110780(n).

2, 5, 9, 10, 38, 47, 1279, 11389

Offset

1,1

Comments

a(8) > 8000. - Michael S. Branicky, Aug 24 2022

Links

Table of n, a(n) for n=1..8.

Prog

(Python)
from sympy import isprime
from itertools import count, islice
def agen(): # generator of terms
    s = ""
    while True:
        for d in "19":
            for k in count(1):
                if isprime(int(s+d*k)): break
            yield k
            s += d*k
print(list(islice(agen(), 7))) # Michael S. Branicky, Aug 24 2022

Crossrefs

Cf. A110774, A110775, A110776, A110777, A110778, A110780.

Sequence in context: A348167 A159073 A088343 * A170838 A115248 A005123

Adjacent sequences: A110778 A110779 A110780 * A110782 A110783 A110784

Keyword

base,nonn,more

Author

Amarnath Murthy, Aug 12 2005

Extensions

More terms from Joshua Zucker, Jan 11 2006

a(7) from Sean A. Irvine, Mar 22 2010

a(8) from Michael S. Branicky, Jun 24 2023

Status

approved