A196750 - OEIS

%I #10 Feb 03 2016 11:40:04

%S 0,1,2,6320

%N Numbers n such that 3, 5, 7 and 11 do not divide swing(n) = A056040(n).

%C It is conjectured that there are no other terms.

%H Peter Luschny, <a href="http://oeis.org/wiki/User:Peter_Luschny/PrimeFactorsSwingingFactorial">On the prime factors of the swinging factorial</a>.

%p # The function Search is defined in A196747.

%p A196750_list := n -> Search(n,[3,5,7,11]):  # n is a search limit

%o (PARI) valp(n,p)=my(s); while(n\=p, s+=n); s

%o is(n)=valp(n,3)==2*valp(n\2,3) && valp(n,5)==2*valp(n\2,5) && valp(n,7)==2*valp(n\2,7) && valp(n,11)==2*valp(n\2,11) \\ _Charles R Greathouse IV_, Feb 02 2016

%Y Cf. A005836, A129508, A030979, A151750, A196747, A196748, A196749.

%K nonn,bref

%O 1,3

%A _Peter Luschny_, Oct 06 2011