A291757 - OEIS

A291757

a(n) = (1/2)*(2 + ((A003557(n)+A046523(n))^2) - A003557(n) - 3*A046523(n)).

1, 2, 2, 12, 2, 16, 2, 59, 18, 16, 2, 80, 2, 16, 16, 261, 2, 94, 2, 80, 16, 16, 2, 355, 33, 16, 129, 80, 2, 436, 2, 1097, 16, 16, 16, 826, 2, 16, 16, 355, 2, 436, 2, 80, 94, 16, 2, 1493, 52, 125, 16, 80, 2, 505, 16, 355, 16, 16, 2, 1832, 2, 16, 94, 4497, 16, 436, 2, 80, 16, 436, 2, 3415, 2, 16, 125, 80, 16, 436, 2, 1493, 888, 16, 2, 1832, 16, 16, 16, 355, 2

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OFFSET

1,2

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..16385

FORMULA

a(n) = (1/2)*(2 + ((A003557(n)+A046523(n))^2) - A003557(n) - 3*A046523(n)).

PROG

(PARI)

A003557(n) = n/factorback(factor(n)[, 1]); \\ From A003557

A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); }; \\ From A046523

A291757(n) = (1/2)*(2 + ((A003557(n)+A046523(n))^2) - A003557(n) - 3*A046523(n));