This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A110781 #20 Jun 24 2023 06:34:57 %S A110781 2,5,9,10,38,47,1279,11389 %N A110781 Number of digits in A110780(n). %C A110781 a(8) > 8000. - _Michael S. Branicky_, Aug 24 2022 %o A110781 (Python) %o A110781 from sympy import isprime %o A110781 from itertools import count, islice %o A110781 def agen(): # generator of terms %o A110781 s = "" %o A110781 while True: %o A110781 for d in "19": %o A110781 for k in count(1): %o A110781 if isprime(int(s+d*k)): break %o A110781 yield k %o A110781 s += d*k %o A110781 print(list(islice(agen(), 7))) # _Michael S. Branicky_, Aug 24 2022 %Y A110781 Cf. A110774, A110775, A110776, A110777, A110778, A110780. %K A110781 base,nonn,more %O A110781 1,1 %A A110781 _Amarnath Murthy_, Aug 12 2005 %E A110781 More terms from _Joshua Zucker_, Jan 11 2006 %E A110781 a(7) from _Sean A. Irvine_, Mar 22 2010 %E A110781 a(8) from _Michael S. Branicky_, Jun 24 2023