[seqfan] A178375
Vladimir Shevelev
shevelev at bgu.ac.il
Wed May 26 16:53:59 CEST 2010
Dear SeqFans,
I have just submitted the following sequence:
%I A178375
%S A178375 2,3,2,5,1,7,2,3,1,11,1,13,1,1,2,17,1,19,1,1,2,23,1,5,1,3,1,29,1,31,2,7,
%T A178375 1,3,1
%N A178375 Let c(n)=gcd(A000032(n)-1,A001608(n)). Then a(n)=1, if c(n)=1; otherwise, a(n) is the maximal prime divisor of c(n) [A000032=Lucas sequence; A001608=Perrin sequence]
%C A178375 If n is prime, then n divides c(n). We call n a Lucas-Perrin pseudoprime if n is composite and divides c(n). Conjecture. Records of the sequence are consecutive primes.
%Y A178375 A000032 A001608
%K A178375 nonn
%O A178375 2,1
Can anyone find a few "Lucas-Perrin pseudoprimes" ? (the drfinition see in %C)
Regards,
Vladimir
Shevelev Vladimir
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