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A114003 Rows sums of triangle A114002. 6
1, 3, 3, 5, 3, 7, 3, 7, 5, 7, 3, 11, 3, 7, 7, 9, 3, 11, 3, 11, 7, 7, 3, 15, 5, 7, 7, 11, 3, 15, 3, 11, 7, 7, 7, 17, 3, 7, 7, 15, 3, 15, 3, 11, 11, 7, 3, 19, 5, 11, 7, 11, 3, 15, 7, 15, 7, 7, 3, 23, 3, 7, 11, 13, 7, 15, 3, 11, 7, 15, 3, 23, 3, 7, 11, 11, 7, 15, 3, 19, 9, 7, 3, 23, 7, 7, 7, 15, 3, 23, 7, 11, 7, 7, 7, 23, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(p) = 3, for primes p.

LINKS

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

FORMULA

a(n) = 2*A000005(n) - 1. - Vladeta Jovovic, Sep 13 2006

Equals A051731 * [1, 2, 2, 2,...]. - Gary W. Adamson, Sep 21 2007

G.f.: Sum_{n>0} x^n*(1+x^n)/(1-x^n). [From Franklin T. Adams-Watters, Oct 09 2009]

PROG

(PARI) N=66; x='x+O('x^N); /* that many terms */

Vec(sum(n=1, N, x^n*(1+x^n)/(1-x^n))) /* show terms */ /* Joerg Arndt, May 25 2011 */

(PARI) A114003(n) = (2*numdiv(n))-1; \\ After Jovovic's formula. Antti Karttunen, May 25 2017

CROSSREFS

Also row sums of triangle A144515. - Gary W. Adamson, Nov 21 2007

Cf. A000005, A051731, A114002.

Sequence in context: A163167 A243729 A200810 * A219792 A029622 A015126

Adjacent sequences:  A114000 A114001 A114002 * A114004 A114005 A114006

KEYWORD

nonn

AUTHOR

Paul Barry, Nov 12 2005

STATUS

approved

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Last modified September 27 06:31 EDT 2021. Contains 347673 sequences. (Running on oeis4.)