1,2

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.)

See A230290.

(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

Cf. A000005, A230290-A230296.

Sequence in context: A121552 A158118 A212137 * A147592 A108885 A072740

Adjacent sequences: A230292 A230293 A230294 * A230296 A230297 A230298

nonn

N. J. A. Sloane, Oct 17 2013

approved