A063998 - OEIS

A063998

Nonsquare, composite numbers k such that Sum_{d|k, d < k/d} s_d = k+1, where s_d is either d+1/(k/d) or (1/d)+(k/d).

42, 48, 60, 72, 120, 132, 216, 240, 264, 312, 330, 360, 396, 420, 432, 440, 448, 456, 480, 504, 528, 540, 546, 560, 600, 612, 620, 630, 648, 672, 684, 700, 704, 720, 756, 768, 780, 792, 810, 812, 840, 864, 924, 936, 960, 990, 1008, 1020, 1040, 1050, 1056

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..51.

EXAMPLE

42 is in the sequence because 1+(1/42) + (1/2)+21 + (1/3)+14 + 6+(1/7) = 42+1.

48 is in the sequence because 1+(1/48) + (1/2)+24 + 3+(1/16) + (1/4)+12 + (1/6)+8 = 48+1.

CROSSREFS

Sequence in context: A276185 A124189 A249043 * A255513 A186456 A181647

Adjacent sequences: A063995 A063996 A063997 * A063999 A064000 A064001

KEYWORD