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.

Showing 1-10 of 14 results. Next

A379438 Triangle read by rows: T(n,k) is the number of sensed combinatorial maps with n edges and genus k, 0 <= k <= floor(n/2).

Original entry on oeis.org

1, 2, 4, 1, 14, 6, 57, 46, 4, 312, 452, 106, 2071, 4852, 2382, 131, 15030, 52972, 46680, 8158, 117735, 587047, 830848, 313611, 14118, 967850, 6550808, 13804864, 9326858, 1369446, 8268816, 73483256, 218353000, 236095958, 74803564, 2976853, 72833730, 827801468, 3328822880, 5345316004, 3023693380, 391288854
Offset: 0

Views

Author

Andrew Howroyd, Jan 16 2025

Keywords

Examples

			Triangle begins:
  n\k     [0]      [1]       [2]      [3]      [4]
  [0]      1;
  [1]      2;
  [2]      4,       1;
  [3]     14,       6;
  [4]     57,      46,        4;
  [5]    312,     452,      106;
  [6]   2071,    4852,     2382,     131;
  [7]  15030,   52972,    46680,    8158;
  [8] 117735,  587047,   830848,  313611,   14118;
  [9] 967850, 6550808, 13804864, 9326858, 1369446;
  ...
		

Crossrefs

Row sums are A170946.
Cf. A269919 (rooted), A379439 (unsensed), A380234 (achiral), A380235.

A379439 Triangle read by rows: T(n,k) is the number of unsensed combinatorial maps with n edges and genus k, 0 <= k <= floor(n/2).

Original entry on oeis.org

1, 2, 4, 1, 14, 6, 52, 40, 4, 248, 320, 76, 1416, 2946, 1395, 82, 9172, 29364, 24950, 4348, 66366, 309558, 427336, 160050, 7258, 518868, 3365108, 6987100, 4696504, 688976, 4301350, 37246245, 109761827, 118353618, 37466297, 1491629, 37230364, 416751008, 1668376886, 2675297588, 1512650776, 195728778
Offset: 0

Views

Author

Andrew Howroyd, Jan 16 2025

Keywords

Examples

			Triangle begins:
  n\k     [0]      [1]      [2]      [3]     [4]
  [0]      1;
  [1]      2;
  [2]      4,       1;
  [3]     14,       6;
  [4]     52,      40,       4;
  [5]    248,     320,      76;
  [6]   1416,    2946,    1395,      82;
  [7]   9172,   29364,   24950,    4348;
  [8]  66366,  309558,  427336,  160050,   7258;
  [9] 518868, 3365108, 6987100, 4696504, 688976;
		

Crossrefs

Row sums are A214816.
Cf. A269919 (rooted), A379438 (sensed), A380234 (achiral), A380235.

Formula

T(n,k) = (A379438(n,k) + A380234(n,k))/2.

A348802 a(n) = number of non-orientable genus 1 maps with n edges.

Original entry on oeis.org

0, 1, 4, 19, 106, 709, 5356, 44558, 397146, 3716039, 35967272, 356784008, 3605014966, 36955965852, 383320824698
Offset: 0

Views

Author

Michael De Vlieger, Nov 01 2021

Keywords

Crossrefs

A348803 a(n) = number of non-orientable genus 2 maps with n edges.

Original entry on oeis.org

0, 0, 2, 16, 137, 1254, 12597, 133518, 1464725, 16373700, 185086459, 2106417804, 24081813881, 276231542440, 3176840637522
Offset: 0

Views

Author

Michael De Vlieger, Nov 01 2021

Keywords

Crossrefs

A348804 a(n) = number of non-orientable genus 3 maps with n edges.

Original entry on oeis.org

0, 0, 0, 8, 128, 1890, 27036, 379491, 5229092, 70805740, 944106760, 12426068215, 161793730426, 2087922762430, 26745380615078
Offset: 0

Views

Author

Michael De Vlieger, Nov 01 2021

Keywords

Crossrefs

A348805 a(n) = number of non-orientable genus 4 maps with n edges.

Original entry on oeis.org

0, 0, 0, 0, 47, 1372, 31007, 611322, 11017122, 186044902, 2992773591, 46378655568, 697928466684, 10257901689164, 147883893647230
Offset: 0

Views

Author

Michael De Vlieger, Nov 01 2021

Keywords

Crossrefs

A348806 a(n) = number of non-orientable genus 5 maps with n edges.

Original entry on oeis.org

0, 0, 0, 0, 0, 473, 22556, 704066, 17691240, 387965547, 7743850792, 144265686318, 2549632137634, 43225637985830, 708619408979790
Offset: 0

Views

Author

Michael De Vlieger, Nov 01 2021

Keywords

Crossrefs

A348807 a(n) = number of non-orientable genus 6 maps with n edges.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 7190, 469632, 18521632, 563764626, 14578260141, 336572753272, 7146006383642, 142229030736882, 2688967762932621
Offset: 0

Views

Author

Michael De Vlieger, Nov 01 2021

Keywords

Crossrefs

A348808 a(n) = number of non-orientable genus 7 maps with n edges.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 144904, 11990766, 571333104, 20460879142, 611002852755, 16057491913346, 383591381459308, 8507419863898968
Offset: 0

Views

Author

Michael De Vlieger, Nov 01 2021

Keywords

Crossrefs

A348809 a(n) = number of non-orientable genus 8 maps with n edges.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 3534490, 352456980, 19724988666, 814875498464, 27678691047563, 817987730593078, 21764920947291140
Offset: 0

Views

Author

Michael De Vlieger, Nov 01 2021

Keywords

Crossrefs

Showing 1-10 of 14 results. Next