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a(1) = 1; for n>1, a(n) = smallest power of 2 not included earlier such that the (n>1) concatenation a(n), a(n-1), ...a(2), a(1) is a prime.
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%I #7 Nov 05 2019 12:30:08

%S 1,4,2,4096,8,16,524288,18446744073709551616,

%T 3064991081731777716716694054300618367237478244367204352,268435456,

%U 14474011154664524427946373126085988481658748083205070504932198000989141204992

%N a(1) = 1; for n>1, a(n) = smallest power of 2 not included earlier such that the (n>1) concatenation a(n), a(n-1), ...a(2), a(1) is a prime.

%e 41,241,4096241, etc. are primes.

%K base,nonn

%O 1,2

%A _Amarnath Murthy_, Nov 04 2003

%E More terms from _David Wasserman_, Sep 13 2005