A278244 Least number with the prime signature of the n-th centered square number (A001844(n)).

1, 2, 2, 4, 2, 2, 6, 2, 6, 2, 6, 6, 2, 6, 2, 6, 6, 2, 6, 2, 4, 12, 2, 30, 2, 2, 6, 6, 24, 2, 2, 6, 2, 6, 2, 2, 30, 6, 6, 2, 6, 30, 2, 6, 6, 6, 12, 2, 6, 12, 2, 6, 6, 12, 6, 6, 6, 6, 12, 6, 2, 30, 6, 6, 6, 2, 30, 6, 6, 2, 2, 12, 2, 6, 6, 6, 6, 6, 60, 2, 6, 6, 2, 6, 2, 2, 30, 2, 30, 6, 2, 30, 6, 30, 6, 30, 24, 2, 6, 2, 2, 30, 2, 12, 2, 6, 30, 6, 30, 2, 2, 6, 6, 6, 6

Offset

0,2

Links

Antti Karttunen, Table of n, a(n) for n = 0..10000

Formula

a(n) = A046523(A001844(n)).

Prog

(PARI)
A046523(n) = my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]) \\ From Charles R Greathouse IV, Aug 17 2011
A001844(n) = 2*((n^2) + n) + 1;
A278244(n) = A046523(A001844(n));
for(n=0, 10000, write("b278244.txt", n, " ", A278244(n)));
(Scheme) (define (A278244 n) (A046523 (A001844 n)))

Crossrefs

Cf. A001844, A046523.

Cf. also A278162, A278254, A278259.

Sequence in context: A175462 A133946 A286250 * A278542 A033722 A320166

Adjacent sequences: A278241 A278242 A278243 * A278245 A278246 A278247

Keyword

nonn

Author

Antti Karttunen, Nov 22 2016

Status

approved