Search: id:A037273
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%I A037273
%S A037273 0,0,0,2,0,1,0,13,2,4,0,1,0,5,4,4,0,1,0,15,1,1,0,2,3,4,4,1,0,2,0,2,1,5,
%T A037273 3,2,0,2,1,9,0,2,0,9,6,1,0,15
%N A037273 Number of steps to reach a prime under "replace n by concatenation of
its prime factors", or -1 if no such number.
%H A037273 P. De Geest, Home
Primes
%H A037273 Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
%e A037273 Starting with 14 we get 14=2*7, 27=3*3*3, 333=3*3*37, 3337=47*71, 4771=13*367,
13367 is prime; so a(14)=5.
%Y A037273 Cf. A037271-A037275, A056938.
%Y A037273 Sequence in context: A049218 A154469 A022902 this_sequence A158924 A025426
A053200
%Y A037273 Adjacent sequences: A037270 A037271 A037272 this_sequence A037274 A037275
A037276
%K A037273 nonn,nice,hard
%O A037273 1,4
%A A037273 N. J. A. Sloane (njas(AT)research.att.com), Jeff Burch (gburch(AT)erols.com)
%E A037273 Starting with 49, no prime has been reached after 79 steps.
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