A068658 - OEIS

%I #12 Mar 27 2024 21:05:14

%S 31,421,521,631,9421,14731,15731,189421,36189421,39199421,492412631,

%T 542713631,603015731,7236189421,7537189421,97482412631,99492412631,

%U 102512512631,107532613631,114572814731,1477336189421,18291452211521,18693462311521,19396482412631

%N Primes in A068657.

%H Michael S. Branicky, <a href="/A068658/b068658.txt">Table of n, a(n) for n = 1..10000</a>

%o (Python)

%o from sympy import isprime

%o from itertools import count, islice

%o def agen(): # generator of terms

%o     for k in count(1):

%o         s = str(k)

%o         while k != 1:

%o             k //= 2

%o             s += str(k)

%o         t = int(str(s))

%o         if isprime(t):

%o             yield t

%o print(list(islice(agen(), 24))) # _Michael S. Branicky_, Mar 27 2024

%Y Cf. A068657.

%K base,nonn

%O 1,1

%A _Amarnath Murthy_, Feb 28 2002

%E More terms from _Sascha Kurz_, Mar 26 2002

%E Corrected and extended by _Sean A. Irvine_, Mar 27 2024