A138881 Array read by rows: row n lists divisors of n-th positive triangular number A000217(n).

1, 1, 3, 1, 2, 3, 6, 1, 2, 5, 10, 1, 3, 5, 15, 1, 3, 7, 21, 1, 2, 4, 7, 14, 28, 1, 2, 3, 4, 6, 9, 12, 18, 36, 1, 3, 5, 9, 15, 45, 1, 5, 11, 55, 1, 2, 3, 6, 11, 22, 33, 66, 1, 2, 3, 6, 13, 26, 39, 78, 1, 7, 13, 91, 1, 3, 5, 7, 15, 21, 35, 105

Offset

1,3

Links

Table of n, a(n) for n=1..72.

Example

Array begins:
1
1, 3
1, 2, 3, 6
1, 2, 5, 10
1, 3, 5, 15
1, 3, 7, 21
1, 2, 4, 7, 14, 28

Crossrefs

Cf. A000217, A133021, A133031, A138882.

Sequence in context: A107341 A209849 A245547 * A070983 A078350 A078719

Adjacent sequences: A138878 A138879 A138880 * A138882 A138883 A138884

Keyword

easy,nonn,tabf

Author

Omar E. Pol, Apr 11 2008

Status

approved