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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.

A260912 Sum over the genera g of the number of immersions of an unoriented circle with n crossings in an unoriented surface of genus g.

Table of values

n a(n)
1 1
2 3
3 12
4 86
5 894
6 14715
7 313364
8 8139398
9 245237925
10 8382002270
11 319994166042
12 13492740284184
13 622738642693202
14 31225868370080949
15 1690360086869176780
16 98252177808632109236
17 6103194081506193327048
18 403488941845715112039425
19 28286698447226523233226110
20 2096044354918091666701275248

List of values

[1, 3, 12, 86, 894, 14715, 313364, 8139398, 245237925, 8382002270, 319994166042, 13492740284184, 622738642693202, 31225868370080949, 1690360086869176780, 98252177808632109236, 6103194081506193327048, 403488941845715112039425, 28286698447226523233226110, 2096044354918091666701275248]

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

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