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 A158320 a(1)=0, a(n) is the smallest nonprime > (n-1)^smallest digit of a(n-1). 0

%I

%S 0,4,18,4,258,26,38,344,513,10,4,14642,14,14,15,16,18,18,20,4,160002,

%T 4,234257,530,4,390626,4,531442,30,4,810001,4,1048577,4,1336338,36,

%U 46657,1874162,39,59320

%N a(1)=0, a(n) is the smallest nonprime > (n-1)^smallest digit of a(n-1).

%e 0, 4(>1=1^0), 20(>18=2^4), 4(>1=3^0), 258(>256=4^4), 26(>25=5^2), 38(>36=6^2), 344(>343=7^3), 513(>512=8^3), 10(>9=9^1), 4(>1=10^1), 14642(>14641=11^4), 14(>12=12^1), 14(>13=13^1), 15(>14=14^1), 16(>15=15^1), 18(>16=16^1), 18(>17=17^1), 20(>18=18^1), 4(>1=19^0), ?(>160000=20^4)

%t nxt[{n_,a_}]:=Module[{k=n^Min[IntegerDigits[a]]+1},While [PrimeQ[k],k++];{n+1,k}]; Transpose[NestList[nxt,{1,0},40]][[2]] (* _Harvey P. Dale_, Apr 17 2015 *)

%Y Cf. A000027, A141468.

%K nonn,base,less

%O 1,2

%A _Juri-Stepan Gerasimov_, Mar 16 2009

%E Corrected (a(3) replaced by 18, duplicate of a(20) removed) and extended by _R. J. Mathar_, May 19 2010

%E Definition corrected by _Harvey P. Dale_, Apr 17 2015

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Last modified December 16 09:06 EST 2019. Contains 330020 sequences. (Running on oeis4.)