A114005 First column of number triangle A114004.

1, -2, -2, 2, -2, 6, -2, -2, 2, 6, -2, -10, -2, 6, 6, 2, -2, -10, -2, -10, 6, 6, -2, 14, 2, 6, -2, -10, -2, -26, -2, -2, 6, 6, 6, 26, -2, 6, 6, 14, -2, -26, -2, -10, -10, 6, -2, -18, 2, -10, 6, -10, -2, 14, 6, 14, 6, 6, -2, 62, -2, 6, -10, 2, 6, -26, -2, -10, 6, -26, -2, -50, -2, 6, -10, -10, 6, -26, -2, -18, 2, 6, -2, 62, 6, 6, 6, 14, -2, 62, 6, -10, 6, 6, 6

Offset: 1

Author

Paul Barry, Nov 12 2005

Keywords

• easy
• sign

Comments

Moebius transform of A114006. - Mats Granvik, Jan 02 2009

Links

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

Crossrefs

Cf. A050328, A114006.

Programs

PARI

A050328(n) = if(1==n,n,sumdiv(n,d,if((dA050328(d),0)));
A114006(n) = ((-1)^bigomega(n) * A050328(n));
A114005(n) = if(1==n,n,2*A114006(n)); \\ Antti Karttunen, May 27 2017

Formula

a(1) = 1, for n > 1, a(n) = 2*A114006(n). - Corrected by Antti Karttunen, May 27 2017

a(1) = 1; a(n) = -2 * Sum_{d|n, d < n} a(d). - Ilya Gutkovskiy, Feb 23 2020

Extensions

More terms from Antti Karttunen, May 27 2017