A079274 Number of divisors associated with the cyclic cases within the n-th group of least prime signatures.

1, 0, 3, 4, 14, 18, 65, 82, 253, 378, 953, 1460, 3667, 5480, 12917, 20582, 45130, 71970, 156510, 248020, 524446, 846962, 1733252, 2806484, 5702101, 9186010, 18375867, 29872508, 58760991, 95500008, 186871472, 302966474, 587603027, 956192230

Offset

0,3

Links

Table of n, a(n) for n=0..33.

Formula

a(n) = A074141(n) - 2* A074141(n-1) for n > 0 and a(0) = 1

Example

The number of divisors doubles each time we create a new "matching" partition by appending "1" to a given partition. Therefore we may write
..1..0..3..4..14..18..65..82..253..378..953...
+ ...2..4.14..36.100.236.602.1368.3242.7240...
= 1..2..7.18..50.118.301.684.1621.3620.8193...

Crossrefs

Cf. A074141.

Sequence in context: A297839 A279938 A280331 * A282421 A282684 A024863

Adjacent sequences: A079271 A079272 A079273 * A079275 A079276 A079277

Keyword

easy,nonn

Author

Alford Arnold, Feb 06 2003

Extensions

More terms from Pab Ter (pabrlos(AT)yahoo.com), May 27 2004

Status

approved