1,2

See also: A000326 Pentagonal numbers: n(3n-1)/2. See also: A007437 Inverse Moebius transform of triangular numbers.

a(n) = SUM[d|n] d*(3*d-1)/2.

Cf. A000326, A007437.

Sequence in context: A117072 A081395 A086224 this_sequence A016071 A086652 A145976

Adjacent sequences: A116910 A116911 A116912 this_sequence A116914 A116915 A116916

easy,nonn

Jonathan Vos Post (jvospost3(AT)gmail.com), Mar 19 2006