A069519 Sum( d divides n,(-1)^d/d) is an integer.

1, 2, 4, 8, 12, 16, 24, 32, 48, 56, 64, 96, 112, 120, 128, 192, 224, 240, 256, 384, 448, 480, 512, 528, 672, 768, 896, 960, 992, 1024, 1056, 1344, 1456, 1536, 1792, 1920, 1984, 2048, 2112, 2160, 2208, 2688, 2912, 3072, 3584, 3840, 3968, 4096, 4224, 4320

Offset

1,2

Links

Table of n, a(n) for n=1..50.

Formula

a(1)=1 a(2)=2 for n>2 a(n)=A066192(n-2)

Crossrefs

Sequence in context: A070173 A363122 A116882 * A363948 A087980 A181818

Adjacent sequences: A069516 A069517 A069518 * A069520 A069521 A069522

Keyword

easy,nonn

Author

Benoit Cloitre, Apr 16 2002

Status

approved