A114005 - OEIS

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

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OFFSET

1,2

COMMENTS

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

LINKS

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

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

PROG

(PARI)

A050328(n) = if(1==n, n, sumdiv(n, d, if((d<n && issquarefree(n/d)), A050328(d), 0)));

A114006(n) = ((-1)^bigomega(n) * A050328(n));

A114005(n) = if(1==n, n, 2*A114006(n)); \\ Antti Karttunen, May 27 2017

CROSSREFS

Cf. A050328, A114006.

Sequence in context: A335966 A292586 A324291 * A103794 A273258 A073124

Adjacent sequences: A114002 A114003 A114004 * A114006 A114007 A114008

KEYWORD

easy,sign

AUTHOR

Paul Barry, Nov 12 2005

EXTENSIONS

More terms from Antti Karttunen, May 27 2017

STATUS

approved