cp's OEIS Frontend

A286243 Filter-sequence: a(n) = A278222(A064216(n)).

%I A286243 #9 May 13 2017 17:23:45
%S A286243 2,2,4,6,2,8,12,4,12,6,6,12,6,2,24,24,8,16,32,12,30,30,4,60,12,12,48,
%T A286243 30,6,60,72,6,6,48,12,12,24,6,12,30,2,48,24,24,60,72,24,36,60,8,12,60,
%U A286243 16,72,180,32,180,24,12,6,12,30,36,24,30,128,210,4,12,30,60,60,30,12,60,210,12,120,120,48,96,120,30,60,48,6,120,60,60,420,180,72,120
%N A286243 Filter-sequence: a(n) = A278222(A064216(n)).
%H A286243 Antti Karttunen, <a href="/A286243/b286243.txt">Table of n, a(n) for n = 1..10000</a>
%H A286243 Indranil Ghosh, <a href="/A286243/a286243.txt">Python program to generate the sequence</a>
%F A286243 a(n) = A278222(A064216(n)).
%o A286243 (PARI)
%o A286243 A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); t }; \\ Modified from code of _M. F. Hasler_
%o A286243 A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ This function from _Charles R Greathouse IV_, Aug 17 2011
%o A286243 A278222(n) = A046523(A005940(1+n));
%o A286243 A064989(n) = {my(f); f = factor(n); if((n>1 && f[1,1]==2), f[1,2] = 0); for (i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f)};
%o A286243 A064216(n) = A064989((2*n)-1);
%o A286243 A286243(n) = A278222(A064216(n));
%o A286243 for(n=1, 10000, write("b286243.txt", n, " ", A286243(n)));
%o A286243 (Scheme) (define (A286243 n) (A278222 (A064216 n)))
%Y A286243 Cf. A064216, A278222, A286250.
%Y A286243 Cf. A254044 (one of the matching sequences).
%K A286243 nonn
%O A286243 1,1
%A A286243 _Antti Karttunen_, May 07 2017