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%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