1,2

a(n)=(1/6)*(55*n^3-75*n^2+26*n)

Cf. A100165 = alternate vertex; A100145 for more on structured numbers.

Sequence in context: A048191 A097199 A100165 this_sequence A100172 A124998 A126419

Adjacent sequences: A100170 A100171 A100172 this_sequence A100174 A100175 A100176

easy,nonn

James A. Record (james.record(AT)gmail.com). Nov 07, 2004.