A064766 Fill a triangular array by rows by writing numbers 1, then 1 up to 2*3/2, then 1 up to 3*4/2, then 1 up to 4*5/2 and so on from 1 up to the n-th triangular number. The final elements of the rows form the sequence.

1, 2, 2, 6, 5, 1, 8, 1, 10, 20, 10, 22, 7, 21, 36, 16, 33, 6, 25, 45, 11, 33, 56, 14, 39, 65, 14, 42, 71, 10, 41, 73, 1, 35, 70, 106, 23, 61, 100, 4, 45, 87, 130, 21, 66, 112, 159, 36, 85, 135, 186, 48, 101, 155, 210, 56, 113, 171, 230, 59, 120, 182, 245, 56, 121, 187

Offset

0,2

Links

Table of n, a(n) for n=0..65.

Example

The array begins
....1
...1.2
..3.1.2
.3.4.5.6
1.2.3.4.5

Crossrefs

Cf. A064865.

Sequence in context: A204991 A054516 A062400 * A019749 A209773 A209767

Adjacent sequences: A064763 A064764 A064765 * A064767 A064768 A064769

Keyword

easy,nonn

Author

Floor van Lamoen, Oct 18 2001

Status

approved