Lily Yen has authored 18 sequences. Here are the ten most recent ones:
A225031
Non-crossing, non-nesting, 5-colored set partitions.
Original entry on oeis.org
1, 6, 41, 321, 2846, 27961, 297681, 3371646, 40065361, 494281201, 6279901766, 81649478161, 1080910639201, 14511820543126, 196956264035481, 2695543342918241, 37127978351861646, 513895401953712521, 7139331902125917361, 99462520534916445006, 1388616983941077336321
Offset: 0
For n=2, a(2)=41 is the number of non-crossing, non-nesting set partitions on 3 elements with 5 possible arc colors.
- Lily Yen, Table of n, a(n) for n = 0..99
- Eric Marberg, Crossings and nestings in colored set partitions, arXiv preprint arXiv:1203.5738 [math.CO], 2012-2013.
- Lily Yen, Crossings and Nestings for Arc-Coloured Permutations, and Arc-coloured permutations, PSAC 2013, Paris, France, June 24-28, Proc. DMTCS (2013) 743-754.
- Lily Yen, Crossings and Nestings for Arc-Coloured Permutations and Automation, Electronic Journal of Combinatorics, 22(1) (2015), #P1.14.
- Index entries for linear recurrences with constant coefficients, signature (41,-638,4701,-16398,21721,-1).
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LinearRecurrence[{41, -638, 4701, -16398, 21721, -1}, {1, 6, 41, 321, 2846, 27961}, 21] (* Jean-François Alcover, Jul 22 2018 *)
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Vec((1 -35*x +433*x^2 -2233*x^3 +4035*x^4 -x^5) / (1 -41*x +638*x^2 -4701*x^3 +16398*x^4 -21721*x^5 +x^6) + O(x^66)) \\ Joerg Arndt, Apr 27 2013
A224993
Non-crossing, non-nesting, 4-colored permutations on {1,2,...,n}.
Original entry on oeis.org
1, 4, 32, 352, 4736, 72832, 1226240, 21948928, 409192448, 7833143296, 152494727168, 3000118779904, 59406517698560, 1180988766453760, 23534128521936896, 469655122210324480, 9380774946206646272, 187467580232576794624, 3747576648059504820224
Offset: 0
For n=3, a(3)=352, the number of ways to color arcs of a permutation on 3 elements in 4 colors so that arcs of the same color do not cross nor nest.
- Lily Yen, Table of n, a(n) for n = 0..99
- Lily Yen, Crossings and Nestings for Arc-Coloured Permutations and Arc-coloured permutations, PSAC 2013, Paris, France, June 24-28, Proc. DMTCS (2013) 743-754.
- Index entries for linear recurrences with constant coefficients, signature (40,-508,2304,-2880).
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Join[{1}, LinearRecurrence[{40, -508, 2304, -2880}, {4, 32, 352, 4736}, 20]] (* Jean-François Alcover, Jul 22 2018 *)
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Vec((1-36*x+380*x^2-1200*x^3+576*x^4)/((1-2*x)*(1-6*x)*(1-12*x)*(1-20*x)) +O(x^66)) \\ Joerg Arndt, Apr 24 2013
A225033
Non-crossing, non-nesting, 7-colored set partitions.
Original entry on oeis.org
1, 8, 71, 715, 8212, 106205, 1514633, 23353828, 383455843, 6630981491, 119760987872, 2243989397161, 43378019032321, 861000869284928, 17476961860459151, 361541275664799595, 7599788958355060972, 161922899182197739685, 3489406153035009734633, 75917779229255330345308
Offset: 0
For n=2, a(2)=71 is the number of non-crossing, non-nesting, 7-colored set partitions on 3 elements.
- Muniru A Asiru, Table of n, a(n) for n = 0..150 (Terms n=0..99 from Lily Yen)
- Eric Marberg, Crossings and nestings in colored set partitions, arXiv preprint arXiv:1203.5738 [math.CO], 2012-2013.
- Lily Yen, Crossings and Nestings for Arc-Coloured Permutations, arXiv:1211.3472 [math.CO], 2012-2013; Formal Power Series and Algebraic Combinatorics Conference, June (2013), to appear.
- Lily Yen, Crossings and Nestings for Arc-Coloured Permutations and Automation, Electronic Journal of Combinatorics, 22(1) (2015), #P1.14.
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seq(coeff(series((1-84*x +2849*x^2 -49873*x^3 +474601*x^4 -2324333*x^5 +4567788*x^6 -x^7) / (1-92*x +3514*x^2 -72168*x^3 +860019*x^4 -5943768*x^5 +22055962*x^6 -33922100*x^7 +x^8),x,n+1), x, n), n = 0 .. 20); # Muniru A Asiru, Feb 22 2019
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a = DifferenceRoot[Function[{a, n}, {a[n] - 33922100*a[n+1] + 22055962*a[n+2] - 5943768*a[n+3] + 860019*a[n+4] - 72168*a[n+5] + 3514*a[n+6] - 92*a[n+7] + a[n+8] == 0, a[0] == 1, a[1] == 8, a[2] == 71, a[3] == 715, a[4] == 8212, a[5] == 106205, a[6] == 1514633, a[7] == 23353828}]];
Table[a[n], {n, 0, 19}] (* Jean-François Alcover, Feb 22 2019 *)
A225032
Non-crossing, non-nesting, 6-colored set partitions.
Original entry on oeis.org
1, 7, 55, 493, 5029, 57379, 716443, 9604345, 136236937, 2022864031, 31180099711, 495615409957, 8079827006125, 134488017925243, 2276945808434659, 39088515241450609, 678651272689389073, 11890942901283331255, 209891714523969067207, 3727004974842239659741
Offset: 0
For n=2, a(2)=55 is the number of non-crossing, non-nesting set partitions on 3 elements with 6 possible arc colors.
- Lily Yen, Table of n, a(n) for n = 0..99
- Eric Marberg, Crossings and nestings in colored set partitions, arXiv preprint arXiv:1203.5738 [math.CO], 2012-2013.
- Lily Yen, Crossings and Nestings for Arc-Coloured Permutations, arXiv:1211.3472 [math.CO], 2012-2013 and Arc-coloured permutations, PSAC 2013, Paris, France, June 24-28, Proc. DMTCS (2013) 743-754.
- Lily Yen, Crossings and Nestings for Arc-Coloured Permutations and Automation, Electronic Journal of Combinatorics, 22(1) (2015), #P1.14.
- Index entries for linear recurrences with constant coefficients, signature (63,-1589,20515,-142915,509549,-727767,1).
A225030
Non-crossing, non-nesting, 4-colored set partitions.
Original entry on oeis.org
1, 5, 29, 193, 1441, 11765, 102701, 941857, 8955937, 87439877, 870218525, 8780788513, 89476873345, 918150779957, 9467752541933, 97965021468865, 1016097175530433, 10556565963815045, 109802406545873309, 1143006276663287809, 11904902286515536609
Offset: 0
For n=3, a(3)=193 is the number of non-crossing, non-nesting, 4-colored set partitions on 4 elements.
- Lily Yen, Table of n, a(n) for n = 0..99
- Eric Marberg, Crossings and nestings in colored set partitions, arXiv preprint arXiv:1203.5738 [math.CO], 2012-2013.
- Lily Yen, Crossings and Nestings for Arc-Coloured Permutations, arXiv:1211.3472 [math.CO], 2012-2013 and Arc-coloured permutations, PSAC 2013, Paris, France, June 24-28, Proc. DMTCS (2013) 743-754
- Lily Yen, Crossings and Nestings for Arc-Coloured Permutations and Automation, Electronic Journal of Combinatorics, 22(1) (2015), #P1.14.
- Index entries for linear recurrences with constant coefficients, signature (25,-218,782,-973,1).
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LinearRecurrence[{25, -218, 782, -973, 1}, {1, 5, 29, 193, 1441}, 25] (* Paolo Xausa, Feb 06 2024 *)
A225029
Non-crossing, non-nesting, 3-colored set partitions.
Original entry on oeis.org
1, 4, 19, 103, 616, 3949, 26545, 184120, 1303135, 9341191, 67490044, 489978217, 3567727441, 26024391436, 190036459099, 1388593185079, 10150390743088, 74215146065461, 542704850311009, 3968914608295360, 29026988765886535, 212297824609934455, 1552734183515322436
Offset: 0
a(3) = 103 is the number of non-crossing, non-nesting, 3-colored set partitions on {1,2,3,4}.
- Muniru A Asiru, Table of n, a(n) for n = 0..1145 (first 100 terms from Lily Yen)
- Eric Marberg, Crossings and nestings in colored set partitions, arXiv preprint arXiv:1203.5738 [math.CO], 2012-2013.
- Lily Yen, Crossings and Nestings for Arc-Coloured Permutations, arXiv:1211.3472 [math.CO], 2012-2013; and Arc-coloured permutations, PSAC 2013, Paris, France, June 24-28, Proc. DMTCS (2013) 743-754
- Lily Yen, Crossings and Nestings for Arc-Coloured Permutations and Automation, Electronic Journal of Combinatorics, 22(1) (2015), #P1.14.
- Index entries for linear recurrences with constant coefficients, signature(14,-59,74,-1).
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a:=[1,4,19,103];; for n in [5..25] do a[n]:=14*a[n-1]-59*a[n-2]+74*a[n-3]-a[n-4]; od; a; # Muniru A Asiru, Dec 18 2018
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I:=[1,4,19,103]; [n le 4 select I[n] else 14*Self(n-1)-59*Self(n-2)+74*Self(n-3)-Self(n-4): n in [1..30]]; // Vincenzo Librandi, Dec 20 2018
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seq(coeff(series((1-10*x+22*x^2-x^3)/(1-14*x+59*x^2-74*x^3+x^4),x,n+1), x, n), n = 0 .. 25); # Muniru A Asiru, Dec 18 2018
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LinearRecurrence[{14, -59, 74, -1}, {1, 4, 19, 103}, 23] (* Jean-François Alcover, Dec 14 2018 *)
CoefficientList[Series[(1 - 10 x + 22 x^2 - x^3) / (1 - 14 x + 59 x^2 - 74 x^3 + x^4), {x, 0, 25}], x] (* Vincenzo Librandi, Dec 20 2018 *)
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Vec((1-10*x+22*x^2-x^3)/(1-14*x+59*x^2-74*x^3+x^4)+O(x^66)) \\ Joerg Arndt, Apr 24 2013
A224992
Non-crossing, non-nesting, 3-colored permutations on {1,2,...,n}.
Original entry on oeis.org
1, 3, 18, 144, 1368, 14400, 160992, 1861632, 21919104, 260508672, 3110985216, 37241118720, 446349219840, 5352925446144, 64215514275840, 770468624990208, 9244918222258176, 110934787001942016, 1331192054033547264, 15974152308466384896, 191688913661984243712
Offset: 0
For n=3, a(3)= 144, the number of ways to color arcs of a permutation on {1,2,3} in 3 colors such that the arcs neither cross nor nest.
- Lily Yen, Table of n, a(n) for n = 0..99
- Wei Chen, Enumeration of Set Partitions Refined by Crossing and Nesting Numbers, MS Thesis, Department of Mathematics. Simon Fraser University, Fall 2014. Table 5.2, r=3.
- Lily Yen, Crossings and Nestings for Arc-Coloured Permutations and Arc-coloured permutations, PSAC 2013, Paris, France, June 24-28, Proc. DMTCS (2013) 743-754.
- Index entries for linear recurrences with constant coefficients, signature (20,-108,144).
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Join[{1}, LinearRecurrence[{20, -108, 144}, {3, 18, 144}, 20]] (* Jean-François Alcover, Jul 22 2018 *)
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Vec((1-17*x+66*x^2-36*x^3)/((1-2*x)*(1-6*x)*(1-12*x))+O(x^66)) \\ Joerg Arndt, Apr 24 2013
A219587
Noncrossing, nonnesting, 2-arc-colored permutations on the set {1..n} where lower arcs even of different colors do not cross.
Original entry on oeis.org
1, 2, 8, 40, 224, 1296, 7568, 44304, 259536, 1520656, 8910160, 52209040, 305919696, 1792542992, 10503446608, 61545189520, 360625475024, 2113093401616, 12381720203088, 72550979111824, 425114158957776, 2490966357221136, 14595875630354000, 85524874633320080
Offset: 0
For n=4, the a(4) = 224 solutions are 24 permutations, 8 of which can be colored in 4 ways each, 8 in 8 ways each, and 8 in 16 ways each, thus resulting in 8 * (4+8+16) = 224.
A193938
3-nonnesting permutations.
Original entry on oeis.org
1, 2, 6, 24, 118, 675, 4333, 30464, 230615, 1856336, 15738672, 139509303, 1285276242, 12248071935, 120255584181, 1212503440774, 12519867688928, 132079067871313, 1420723274988736, 15554956521285848
Offset: 1
A193937
6-nonnesting permutations.
Original entry on oeis.org
1, 2, 6, 24, 120, 720, 5040, 40320, 362880, 3628800, 39916680, 478991641, 6226516930, 87157924751, 1306945300264
Offset: 1
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