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%I #4 Dec 05 2013 19:55:05
%S 11,41,101,401,641,1601,4001,4111,4441,10111,10141,11161,11411,14011,
%T 14401,14411,16001,16111,16141,16411,25601,40111,40961,41011,41141,
%U 41161,41411,41611,41641,44041,44101,44111
%N Primes which can be expressed as concatenation of powers of 4 and 0's.
%e 641 is a term as it is a concatenation of 64 and 1 which are powers of 4.
%K base,easy,nonn
%O 1,1
%A _Amarnath Murthy_, Dec 21 2001
%E Corrected and extended by Christopher Lund (clund(AT)san.rr.com), Apr 14 2002