cp's OEIS Frontend

A097463 Let P(i) = i-th prime. To get a(n), factor P(n)-1 as a product of primes, then concatenate the exponents.

%I A097463 #9 Oct 25 2015 17:33:41
%S A097463 0,1,2,11,101,21,4,12,10001,2001,111,22,301,1101,100000001,200001,
%T A097463 1000000001,211,11001,1011,32,110001,1000000000001,30001,51,202,
%U A097463 1100001,1000000000000001,23,4001,1201,101001,3000001,110000001,200000000001
%N A097463 Let P(i) = i-th prime. To get a(n), factor P(n)-1 as a product of primes, then concatenate the exponents.
%C A097463 If P(n)-1 = P(1)^a * P(2)^b *....* P(j)^k then a(n) = ab...k.
%e A097463 3-1=2^1, so a(2)=1.
%e A097463 5-1=2^2, so a(3)=2.
%e A097463 7-1=2^1*3^1, so a(4)=11.
%e A097463 23=(2^1)*(11^1)+1. So a(9) = 10001.
%e A097463 37 = 36 + 1 = 2^2*3^2 + 1, so 37 becomes 22 (a=2,b=2).
%o A097463 (PARI) {forprime(p=2,150,f=factor(p-1);j=1;q=2;s="0";while(j<=matsize(f)[1], if(q==f[j,1],s=concat(s,f[j,2]);j++,s=concat(s,0));q=nextprime(q+1));print1(eval(s),","))} \\ _Klaus Brockhaus_, Apr 25 2005
%Y A097463 Cf. A037916.
%K A097463 nonn,base
%O A097463 1,3
%A A097463 _Pierre CAMI_, Aug 23 2004
%E A097463 More terms from _Klaus Brockhaus_, Apr 25 2005
%E A097463 a(9) corrected by Dennis (tuesdayist(AT)juno.com), Mar 30 2006