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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.

A260847 Sum over the genera g of the number of immersions of an unoriented circle with n crossing in an oriented surface of genus g.

Table of values

n a(n)
1 1
2 3
3 13
4 121
5 1538
6 28010
7 618243
8 16223774
9 490103223
10 16761330464
11 639968394245
12 26985325092730
13 1245476031528966
14 62451726249369666
15 3380720083302727868
16 196504354812897344692
17 12206388155663897395208
18 806977883622439156487124
19 56573396893789449427353609
20 4192088709829643732598955348

List of values

[1, 3, 13, 121, 1538, 28010, 618243, 16223774, 490103223, 16761330464, 639968394245, 26985325092730, 1245476031528966, 62451726249369666, 3380720083302727868, 196504354812897344692, 12206388155663897395208, 806977883622439156487124, 56573396893789449427353609, 4192088709829643732598955348]

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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