A211217 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

A211217

Maximum of sigma(x) * sigma(y), where x + y = n.

1, 3, 9, 12, 21, 28, 49, 48, 84, 72, 144, 96, 180, 156, 225, 195, 336, 234, 420, 364, 504, 360, 784, 432, 672, 672, 868, 576, 1092, 744, 1176, 936, 1209, 1008, 1680, 992, 1638, 1440, 1860, 1344, 2340, 1344, 2520, 1920, 2232, 1680, 3600, 1860, 3024, 2400

(list; graph; refs; listen; history; text; internal format)

OFFSET

2,2

LINKS

Paolo P. Lava, Table of n, a(n) for n = 2..10000

Paolo P. Lava, Plot of the first 10000 terms of the sequence

EXAMPLE

For n=83 the maximum product is reached when 35 and 48 (35+48=83) are considered: sigma(35)*sigma(48) = 48*124 = 5952.

For n=99 the maximum product is reached when 36 and 63 (36+63=99) are considered: sigma(36)*sigma(63) = 91*104 = 9464.

MAPLE

with(combstruct); with(numtheory);

A211217:=proc(i)