A110789 - OEIS

%I #17 Nov 21 2024 06:12:02

%S 1,1,2,4,5,10,23,102,102,138,451,1922,1624,5630,26410

%N Number of digits in A110788(n).

%o (Python)

%o from sympy import isprime

%o from itertools import count, islice

%o def agen(): # generator of terms

%o     s = ""

%o     while True:

%o         for d in "71":

%o             for k in count(1):

%o                 if isprime(int(s+d*k)): break

%o             yield k

%o             s += d*k

%o print(list(islice(agen(), 11))) # _Michael S. Branicky_, Aug 23 2022

%Y Cf. A110774, A110775, A110776, A110777, A110778, A110780, A110781, A110782, A110783, A110788.

%K base,nonn,more

%O 1,3

%A _Amarnath Murthy_, Aug 13 2005

%E More terms from _Joshua Zucker_, Jan 11 2006

%E a(12) from _Sean A. Irvine_, Mar 22 2010

%E a(13)-a(14) from _Michael S. Branicky_, Aug 23 2022

%E a(15) from _Michael S. Branicky_, Nov 20 2024