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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A274343 Irregular triangle read by rows giving the denominators of the coefficients of the Eisenstein series G_{2*n} multiplied by 2*n-1, for n >= 2. Also Laurent coefficients of Weierstrass's P function.

Original entry on oeis.org

1, 1, 3, 11, 13, 39, 33, 2431, 663, 247, 2717, 80223, 1989, 1062347, 3187041, 16055, 6605027, 77571, 11685817, 1062347, 2002524095, 4405553009, 247, 2717, 497705, 155409680283, 11559397707, 1123416017295, 74894401153, 114727509, 5643476995, 409716429837, 10158258591, 909705199, 233400836858808047, 190964321066297493, 18394643943, 34825896536145, 229850917138557, 17096349208653, 357856262339147, 24291640943843637507, 602272089516784401, 174041631153
Offset: 2

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Author

Wolfdieter Lang, Jun 20 2016

Keywords

Comments

The length of row n is A008615(n), n >= 2.
The numerator triangle is given in A274342 where also details and references are given.
a(n) = denominator(r(n)) where the rationals r(n) are reduced to lowest terms obtained from the c(n) recurrence given in a comment of A274342 as coefficients of powers of c2 and c3 corresponding to the partitions of n with parts 2 and 3 only, when sorted with increasing number of parts.

Examples

			The irregular triangle a(n, m) begins:
n\m             1            2            3
2:              1
3:              1
4:              3
5:             11
6:             13           39
7:             33
8:           2431          663
9:            247         2717
10:          8022         1989
11:       1062347      3187041
12:         16055      6605027        77571
13:      11685817      1062347
14:    2002524095   4405553009       249951
15:        497705 155409680283  11559397707
16: 1123416017295  74894401153    114727509
17:    5643476995 409716429837  10158258591
...
row n = 18: 909705199 233400836858808047 190964321066297493 18394643943,
row n = 19: 34825896536145  229850917138557 17096349208653,
row n = 20: 357856262339147 24291640943843637507 602272089516784401 174041631153.
...
For the rationals r(n), n = 2..20, see A274342.
		

Crossrefs

Cf. A274342.
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