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Number of cyclic permutations of the digits of n which give primes.
2

%I #12 Aug 05 2015 14:12:56

%S 0,1,1,0,1,0,1,0,0,0,2,0,2,1,0,1,2,0,1,1,0,0,1,0,0,0,0,0,1,1,2,1,0,1,

%T 1,0,2,1,0,0,1,0,1,0,0,0,1,0,0,1,0,0,1,0,0,0,0,0,1,0,1,0,0,0,0,0,1,0,

%U 0,1,2,0,2,1,0,1,0,0,2,0,0,0,1,0,0,0,0,0,1,0,1,1,0,0,1,0,2,1,0,0,2,0,2,1,0

%N Number of cyclic permutations of the digits of n which give primes.

%H Robert Israel, <a href="/A061264/b061264.txt">Table of n, a(n) for n = 1..10000</a>

%e a(157) = 2 as among the three cyclic permutations 157, 571, 715, two are primes.

%p A055642 := proc(n) max(1,ilog10(n)+1) ; end: A061264 := proc(n) local ncyc,s,dgs,a,L,i ; a := 0 ; dgs := convert(n,base,10) ; ncyc := n ; for s from 1 to A055642(n) do if isprime(ncyc) then a := a+1 ; fi; L := ListTools[Rotate](dgs,s) ; ncyc := add(op(i,L)*10^(i-1),i=1..nops(L)) ; od: RETURN(a) ; end: for n from 1 to 120 do printf("%d,",A061264(n)) ; od: # _R. J. Mathar_, Oct 02 2008

%Y Cf. A039999.

%Y Cf. A046810. - _R. J. Mathar_, Oct 02 2008

%K nonn,base

%O 1,11

%A _Amarnath Murthy_, Apr 24 2001

%E More terms from _R. J. Mathar_, Oct 02 2008

%E Offset corrected, _Joerg Arndt_, Aug 05 2015