cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A265141 Irregular table read by rows: n-th row lists the 9 n-gonal numbers of a 3 X 3 semimagic square with the smallest magic sum. The terms of each row are arranged in the manner shown in A261816.

Original entry on oeis.org

15, 66, 630, 231, 435, 45, 465, 210, 36, 16, 529, 2704, 1024, 1936, 289, 2209, 784, 256, 651, 54626, 356972, 135751, 241001, 35497, 275847, 116622, 19780, 6, 39621, 481671, 158766, 345696, 16836, 362526, 135981, 22791, 697, 93799, 662290, 298771, 448804, 9211, 457318, 214183, 85285
Offset: 3

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Author

Arkadiusz Wesolowski, Dec 02 2015

Keywords

Comments

The squares presented in this sequence are basic semimagic. For a definition of basic semimagic squares, see A261816.
The magic constants are, respectively: 711 = A269060(1), 3249 = 57^2 = A269061(1), and 412249.

Examples

			The semimagic squares are:
triangular numbers
|---|---|---|
| 15| 66|630|
|---|---|---|
|231|435| 45|
|---|---|---|
|465|210| 36|
|---|---|---|
.
square numbers
|----|----|----|
| 16 | 529|2704|
|----|----|----|
|1024|1936| 289|
|----|----|----|
|2209| 784| 256|
|----|----|----|
.
pentagonal numbers
|------|------|------|
|  651 | 54626|356972|
|------|------|------|
|135751|241001| 35497|
|------|------|------|
|275847|116622| 19780|
|------|------|------|
		

Crossrefs

Extensions

More terms from Arkadiusz Wesolowski, Apr 03 2016

A261815 Total number of semimagic squares of order n that can be formed from the numbers 1, ..., n^2.

Original entry on oeis.org

1, 0, 72, 549504, 4632344409600
Offset: 1

Views

Author

Arkadiusz Wesolowski, Nov 18 2015

Keywords

Crossrefs

Formula

a(n) = A261816(n)*A048617(n) for n > 1.
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