

A230291


a(n) = Sum_{i=1..n} d(24*i+17)  Sum_{i=1..n} d(6*i+5), where d(n) = A000005(n).


3



0, 2, 2, 2, 0, 2, 4, 6, 6, 4, 4, 4, 6, 6, 6, 6, 10, 10, 10, 10, 10, 12, 10, 10, 8, 6, 12, 14, 16, 16, 16, 18, 16, 18, 16, 14, 16, 16, 16, 12, 18, 22, 22, 24, 20, 22, 22, 24, 22, 20, 22, 28, 26, 26, 26, 24, 26, 26, 26, 26, 24, 28, 30, 30, 30, 30, 34, 34, 36, 32, 32, 32, 34, 36, 32, 34, 36, 34, 34, 34, 36, 36, 40, 42
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OFFSET

1,2


LINKS

Robert Israel, Table of n, a(n) for n = 1..10000
Jorge Luis Cimadevilla Villacorta, Certain inequalities associated with the divisor function, Amer. Math. Monthly, 120 (2013), 832837. (Shows that a(n) >= 0.)


MAPLE

See A230290.


PROG

(PARI) vector(100, n, sum(i=1, n, numdiv(24*i+17))  sum(i=1, n, numdiv(6*i+5))) \\ Michel Marcus, Oct 09 2014
(MAGMA) [&+[#Divisors(24*i+17):i in [1..n]] &+[#Divisors(6*i+5):i in [1..n]]:n in [1..90]]; // Marius A. Burtea, Jan 03 2020


CROSSREFS

Cf. A000005, A230290, A230292, A230293, A230294, A230295, A230296.
Sequence in context: A264136 A274850 A215594 * A059288 A319109 A217670
Adjacent sequences: A230288 A230289 A230290 * A230292 A230293 A230294


KEYWORD

nonn


AUTHOR

N. J. A. Sloane, Oct 17 2013


STATUS

approved



