1,4

Obviously all the terms are odd.

Table of n, a(n) for n=1..75.

The arithmetic progression in triangular form:

1

1 2

1 2 3

1 4 7 10

1 8 15 22 29

1 6 11 16 21 26

...

Cf. A084727.

Sequence in context: A200285 A205528 A021731 * A107738 A341628 A238048

Adjacent sequences: A084723 A084724 A084725 * A084727 A084728 A084729

nonn

Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), Jun 13 2003

More terms from David Wasserman, Jan 03 2005

Example triangle corrected by Nathaniel Johnston, Jun 25 2011

approved