1,2

a(n) = a(n-1) + q^{(n-1)} = {(q^n - 1) / (q - 1)}

Sequence in context: A076901 A080043 A113022 this_sequence A015531 A083425 A100237

Adjacent sequences: A014983 A014984 A014985 this_sequence A014987 A014988 A014989

sign,easy

Olivier Gerard (ogerard(AT)ext.jussieu.fr)