A348999 - OEIS

%I #16 Nov 13 2021 22:32:56

%S 1,1,1,6,1,6,1,2,3,6,3,18,1,2,3,6,9,18,1,2,3,6,9,18,1,2,3,6,9,18,1,2,

%T 1,6,1,6,1,2,3,6,3,18,1,2,3,6,9,18,1,2,3,6,9,18,1,2,3,6,9,18,1,2,1,6,

%U 1,6,1,2,3,6,3,18,1,2,3,6,9,18,1,2,3,6,9,18,1,2,3,6,9,18,1,2,1,6,1,6,1,2,3,6,3,18

%N a(n) = A348929(A276086(n)), where A348929(n) = gcd(n, A003959(n)), A003959 is multiplicative with a(p^e) = (p+1)^e, and A276086 gives the prime product form of primorial base expansion of n.

%C After each primorial number (A002110), the apparent periodicity grows more complex.

%H Antti Karttunen, <a href="/A348999/b348999.txt">Table of n, a(n) for n = 0..11550</a>

%H <a href="/index/Pri#primorialbase">Index entries for sequences related to primorial base</a>

%F a(n) = A348929(A276086(n)).

%F a(n) = gcd(A276086(n), A348949(n)) = gcd(A276086(n), A348950(n)).

%o (PARI) A348999(n) = { my(m1=1, m2=1, p=2); while(n, m1 *= (p^(n%p)); m2 *= ((1+p)^(n%p)); n = n\p; p = nextprime(1+p)); gcd(m1,m2); };

%Y Cf. A002110, A003959, A276086, A348929, A348949, A348950, A348998, A349000.

%K nonn,base,look

%O 0,4

%A _Antti Karttunen_, Nov 07 2021