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

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, 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, 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

Offset

1,1

Links

Antti Karttunen, Table of n, a(n) for n = 1..10000

Indranil Ghosh, Python program to generate the sequence

Formula

a(n) = A278222(A064216(n)).

Prog

(PARI)
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
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
A278222(n) = A046523(A005940(1+n));
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)};
A064216(n) = A064989((2*n)-1);
A286243(n) = A278222(A064216(n));
for(n=1, 10000, write("b286243.txt", n, " ", A286243(n)));
(Scheme) (define (A286243 n) (A278222 (A064216 n)))

Crossrefs

Cf. A064216, A278222, A286250.

Cf. A254044 (one of the matching sequences).

Sequence in context: A207193 A319579 A286631 * A368259 A305125 A260095

Adjacent sequences: A286240 A286241 A286242 * A286244 A286245 A286246

Keyword

nonn

Author

Antti Karttunen, May 07 2017

Status

approved