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%I #7 Mar 14 2015 15:37:08
%S 21,48034,69926,180461,214591,409473,563715,41630193,253385633342,
%T 661494322636
%N Numbers n such that n is R(n)-th composite number where R(n) is the digit reversal of n (A002808(A004086(n))=n).
%C There is no further term < 3*10^9.
%C a(11) > 3*10^12. [_Donovan Johnson_, Jun 14 2009]
%e 41630193 is in the sequence because 41630193 is the 39103614th composite number.
%t Do[s=FromDigits[Reverse[IntegerDigits[n]]];If[s<n&&!PrimeQ[n] &&s==n-PrimePi[n]-1, Print[n]], {n, 2, 42000000}]
%Y Cf. A002808, A004086, A100412, A100413, A100415.
%K base,more,nonn
%O 1,1
%A _Farideh Firoozbakht_, Dec 10 2004
%E a(9)-a(10) from _Donovan Johnson_, Jun 14 2009
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