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A230295 a(n) = Sum_{i=1..n} d(8*i+5) - Sum_{i=1..n} d(4*i+3), where d(n) = A000005(n). 3
0, 2, 0, 0, 4, 2, 2, 2, 2, 4, 6, 4, 2, 6, 4, 6, 8, 4, 4, 10, 8, 6, 10, 6, 8, 10, 10, 8, 8, 10, 12, 16, 10, 10, 14, 10, 12, 12, 10, 14, 18, 16, 12, 18, 18, 16, 18, 12, 12, 18, 16, 16, 20, 20, 22, 24, 18, 18, 22, 20, 20, 22, 16, 16, 26, 26, 26, 26, 22, 24, 24, 24, 24, 24, 26, 26, 32, 24, 26, 30, 28, 28, 28, 26, 26, 36 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..86.

Jorge Luis Cimadevilla Villacorta, Certain inequalities associated with the divisor function, Amer. Math. Monthly, 120 (2013), 832-837. (Shows that a(n) >= 0.)

MAPLE

See A230290.

PROG

(PARI) vector(100, n, sum(i=1, n, numdiv(8*i+5)) - sum(i=1, n, numdiv(4*i+3))) \\ Michel Marcus, Oct 09 2014

CROSSREFS

Cf. A000005, A230290-A230296.

Sequence in context: A121552 A158118 A212137 * A147592 A108885 A072740

Adjacent sequences:  A230292 A230293 A230294 * A230296 A230297 A230298

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Oct 17 2013

STATUS

approved

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Last modified April 1 10:33 EDT 2020. Contains 333159 sequences. (Running on oeis4.)