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A230292 a(n) = Sum_{i=1..n} d(24*i+9) - Sum_{i=1..n} d(6*i+3), where d(n) = A000005(n). 3
1, 1, 2, 6, 6, 8, 6, 6, 11, 9, 13, 15, 14, 18, 20, 18, 14, 19, 21, 21, 25, 21, 25, 31, 33, 33, 31, 29, 33, 36, 32, 32, 34, 40, 40, 42, 41, 37, 49, 51, 51, 49, 47, 51, 52, 54, 50, 54, 54, 58, 60, 52, 56, 64, 62, 66, 68, 64, 68, 74, 72, 68, 73, 75, 75, 75, 77, 77, 85, 83, 79, 77, 72, 84, 88, 88, 84, 92, 94, 90, 98, 90 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..82.

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(24*i+9)) - sum(i=1, n, numdiv(6*i+3))) \\ Michel Marcus, Oct 09 2014

CROSSREFS

Cf. A000005, A230290-A230296.

Sequence in context: A177934 A318435 A157299 * A082911 A005869 A021978

Adjacent sequences:  A230289 A230290 A230291 * A230293 A230294 A230295

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Oct 17 2013

STATUS

approved

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Last modified December 3 17:23 EST 2021. Contains 349467 sequences. (Running on oeis4.)