A305808 Dirichlet convolution of A032742 (the largest proper divisor of n) with itself.

1, 2, 2, 5, 2, 8, 2, 12, 7, 12, 2, 22, 2, 16, 12, 28, 2, 30, 2, 34, 16, 24, 2, 56, 11, 28, 24, 46, 2, 56, 2, 64, 24, 36, 16, 87, 2, 40, 28, 88, 2, 76, 2, 70, 46, 48, 2, 136, 15, 70, 36, 82, 2, 108, 24, 120, 40, 60, 2, 172, 2, 64, 62, 144, 28, 116, 2, 106, 48, 108, 2, 228, 2, 76, 70, 118, 24, 136, 2, 216, 81, 84, 2, 236, 36, 88, 60, 184, 2, 228, 28

Offset

1,2

Links

Antti Karttunen, Table of n, a(n) for n = 1..65537

Formula

a(n) = Sum_{d|n} A032742(n/d)*A032742(d).

Prog

(PARI)
A032742(n) = if(1==n, n, n/vecmin(factor(n)[, 1]));
A305808(n) = sumdiv(n, d, A032742(n/d)*A032742(d));

Crossrefs

Cf. A032742, A300236, A300239, A305807.

Sequence in context: A293225 A353851 A305798 * A353858 A347466 A266662

Adjacent sequences: A305805 A305806 A305807 * A305809 A305810 A305811

Keyword

nonn

Author

Antti Karttunen, Jun 13 2018

Status

approved