A333915 - OEIS

A333915

Number of ways to represent n as a pyramidal number.

1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 2, 1, 1, 1, 2, 1, 1, 1, 3, 1, 1, 1, 2, 2, 1, 1, 2, 1, 2, 1, 2, 1, 1, 1, 2, 1, 1, 1, 3, 1, 1, 1, 2, 2, 2, 1, 2, 1, 2, 1, 2, 1, 1, 1, 2, 1, 1, 1, 3, 1, 1, 1, 2, 2, 1, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 1, 1, 3, 2, 1, 1, 2, 2, 1, 1, 2, 1, 2

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OFFSET

4,7

COMMENTS

Frequency of n in the array A261720 of pyramidal numbers.

LINKS

Table of n, a(n) for n=4..100.

Eric Weisstein's World of Mathematics, Pyramidal Number

Index to sequences related to pyramidal numbers

EXAMPLE

a(10) = 2 because 10 is the third tetrahedral (or triangular pyramidal) number and also the second 9-gonal pyramidal number.

a(30) = 3 because 30 is the fourth square pyramidal number, the third octagonal pyramidal number and also the second 29-gonal pyramidal number.