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Numbers k such that the decimal expansion of k and 14^k both begin with 14.
1

%I #10 Jul 01 2023 16:54:00

%S 1404,1445,1486,1493,14023,14071,14112,14153,14160,14201,14242,14283,

%T 14290,14331,14372,14379,14420,14461,14502,14509,14550,14591,14639,

%U 14680,14721,14728,14769,14810,14851,14858,14899,14940,14947,14988,140029,140070,140118,140159

%N Numbers k such that the decimal expansion of k and 14^k both begin with 14.

%C Subsequence of A352179.

%H Chai Wah Wu, <a href="/A352239/b352239.txt">Table of n, a(n) for n = 1..4098</a>

%e Both 1404 and 14^1404 = 1458... start with the digits 14.

%o (Python)

%o from itertools import count, islice

%o def A352239_gen(): # generator of terms

%o for l in count(0):

%o k14 = 14**(14*10**l)

%o for k in range(14*10**l,15*10**l):

%o if str(k14)[:2] == '14':

%o yield k

%o k14 *= 14

%o A352239_list = list(islice(A352239_gen(),20))

%Y Cf. A352179.

%K nonn,base

%O 1,1

%A _Chai Wah Wu_, Mar 08 2022