Hexagonal pyramidal number

A hexagonal pyramidal number is a pyramidal number formed by adding the first few hexagonal numbers. The first few of these numbers are:

1, 7, 22, 50, 95, 161, 252, 372, 525, 715, 946, 1222, 1547, 1925 (sequence A002412 in the OEIS).

The nth number in this sequence is given by the formula

References


fonte: https://web.archive.org/web/20170320162456/https://en.wikipedia.org/wiki/Hexagonal_pyramidal_number