1,2

a(4) = 18 = sum of row 4 terms of triangle A132789: (1 + 8 + 8 + 1).

Cf. A132789.

Sequence in context: A005507 A094864 A120010 this_sequence A072850 A072852 A072853

Adjacent sequences: A132787 A132788 A132789 this_sequence A132791 A132792 A132793

nonn

Gary W. Adamson (qntmpkt(AT)yahoo.com), Aug 30 2007