A359321 a(n) is the smallest n-gonal pyramidal number which can be represented as the sum of n distinct nonzero n-gonal pyramidal numbers in exactly n ways, or -1 if none exists.

2300, 6201, 8125, 6391

Offset

3,1

Links

Table of n, a(n) for n=3..6.

Eric Weisstein's World of Mathematics, Pyramidal Number

Example

For n = 3: 2300 = 1 + 969 + 1330 = 56 + 220 + 2024 = 165 + 364 + 1771.
For n = 4: 6201 = 1 + 91 + 1785 + 4324 = 1 + 285 + 1015 + 4900 = 30 + 140 + 506 + 5525 = 91 + 819 + 1496 + 3795.

Crossrefs

Cf. A080851, A350210, A350397, A350423.

Sequence in context: A083572 A270854 A260292 * A339349 A281927 A179699

Adjacent sequences: A359318 A359319 A359320 * A359322 A359323 A359324

Keyword

nonn,more

Author

Ilya Gutkovskiy, Dec 25 2022

Status

approved