A heptagonal pyramidal number is the sum of the first few heptagonal numbers. The heptagonal number for n can be calculated by adding up the heptagonal numbers for 1 to n, or by using the formula n(n + 1)(5n - 2)/6.
The first few heptagonal pyramidal numbers are:
1, 8, 26, 60, 115, 196, 308, 456, 645, 880, 1166, 1508, 1911, 2380, 2920, 3536, 4233, 5016, 5890, 6860, 7931, 9108 (sequence A002413 in OEIS)
Famous quotes containing the word number:
“Strange goings on! Jones did it slowly, deliberately, in the bathroom, with a knife, at midnight. What he did was butter a piece of toast. We are too familiar with the language of action to notice at first an anomaly: the ‘it’ of ‘Jones did it slowly, deliberately,...’ seems to refer to some entity, presumably an action, that is then characterized in a number of ways.”
—Donald Davidson (b. 1917)