

A134000


Array read by antidiagonals: row n contains the positive integers each with exactly n positive "nonisolated divisors". A divisor, k, of n is nonisolated if (k1) or (k+1) also divides n.


1



2, 6, 4, 12, 18, 8, 30, 20, 54, 10, 60, 42, 24, 66, 14, 90, 72, 126, 36, 78, 16, 180, 168, 84, 150, 40, 102, 22, 360, 210, 270, 120, 294, 48, 114, 26, 630, 660, 240, 330, 132, 306, 56, 138, 28, 420, 924, 1080, 480, 336, 144, 342, 80, 162, 32, 840, 720, 1200, 1092, 504
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OFFSET

2,1


COMMENTS

The left column (column 1) of the array is sequence A133996. This array written as a sequence is a permutation of the even positive integers. The array starts at column 1 and row 2. (There are no integers with exactly 1 nonisolated divisor.)


LINKS

Table of n, a(n) for n=2..61.


EXAMPLE

2 nonisolated divisors: 2, 4, 8, 10, 14, ...
3 nonisolated divisors: 6, 18, 54, 66, ...
4 nonisolated divisors: 12, 20, 24, ...
etc.


CROSSREFS

Cf. A134001, A133996.
Sequence in context: A145177 A007517 A072946 * A127730 A118416 A046204
Adjacent sequences: A133997 A133998 A133999 * A134001 A134002 A134003


KEYWORD

nonn,tabl


AUTHOR

Leroy Quet, Oct 01 2007


EXTENSIONS

Extended by Ray Chandler, Jun 25 2008


STATUS

approved



