Search: id:A068185
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%I A068185
%S A068185 0,2,3,81,1,102136,1,1389537,317811,4972825,0,12718670252691776,0,4506838380,
%T A068185 11472991008,53560898629395777,0,514875062240230100091396,0,164997736300578242823300,
%U A068185 241098942106440,0,0,3203410440031870942324022423896806853153460,1,0,61305790721611591
%N A068185 Number of ways writing n^n as a product of decimal digits of some other 
               number which has no digits equal to 1.
%C A068185 a(n)= 0 when n has prime-factor larger than 7 [so A067734(n)=0] or when 
               n is in A068191, i.e. not in A002473.
%F A068185 a(n) = A067734(n^n) = A067734(A000312(n))
%e A068185 n=1 has no solution; a(2)=A000073(6)=2 with {4,22} solutions; a(3)=A067734(27)=3=Fibonacci[4]; 
               n=5 and n=7, n^n has single prime factor of which any true multiple 
               have 2 digits so 55555 and 7777777 are the only solutions, so a(5)=a(7)=1; 
               a(4)=A067734(256)=81=A000073(10); a(8)=A067734(2^24)=A000073(26)=1389537; 
               n=9 a(9)=A067734(3^27)=Fibonacci(28)=A000045(28)=317811.
%Y A068185 Cf. A000045, A000073, A000312, A001222, A002473, A067734, A068183-A068187, 
               A068189-A068191.
%Y A068185 Sequence in context: A042233 A091825 A166091 this_sequence A037391 A037427 
               A042549
%Y A068185 Adjacent sequences: A068182 A068183 A068184 this_sequence A068186 A068187 
               A068188
%K A068185 base,nonn
%O A068185 1,2
%A A068185 Labos E. (labos(AT)ana.sote.hu), Feb 19 2002
%E A068185 Edited By Henry Bottomley (se16(AT)btinternet.com), Feb 26 2002.
%E A068185 Edited and extended by Max Alekseyev (maxale(AT)gmail.com), Sep 19 2009

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