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.

User: Lily Yen

Lily Yen's wiki page.

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

Author

Lily Yen, Apr 25 2013

Keywords

Examples

			For n=2, a(2)=41 is the number of non-crossing, non-nesting set partitions on 3 elements with 5 possible arc colors.
		

Programs

  • Mathematica
    LinearRecurrence[{41, -638, 4701, -16398, 21721, -1}, {1, 6, 41, 321, 2846, 27961}, 21] (* Jean-François Alcover, Jul 22 2018 *)
  • PARI
    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

Formula

G.f.: (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).

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

Author

Lily Yen, Apr 24 2013

Keywords

Comments

A225029-A225033 are sequences counting non-crossing, non-nesting, r-colored set partitions for r=3..7. Set partitions only have upper arcs, whereas permutations have upper and lower arcs in their annotated arc diagram representations.

Examples

			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.
		

Programs

  • Mathematica
    Join[{1}, LinearRecurrence[{40, -508, 2304, -2880}, {4, 32, 352, 4736}, 20]] (* Jean-François Alcover, Jul 22 2018 *)
  • PARI
    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

Formula

G.f.: (1-36*x+380*x^2-1200*x^3+576*x^4)/((1-2*x)*(1-6*x)*(1-12*x)*(1-20*x)).
a(n) = 2^(n-1)*(20*3^n+7*6^n+10^n+28)/35 for n>0, a(0)=1. [Bruno Berselli, Apr 26 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

Author

Lily Yen, Apr 25 2013

Keywords

Examples

			For n=2, a(2)=71 is the number of non-crossing, non-nesting, 7-colored set partitions on 3 elements.
		

Programs

  • Maple
    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
  • Mathematica
    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 *)

Formula

G.f.: (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).

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

Author

Lily Yen, Apr 25 2013

Keywords

Examples

			For n=2, a(2)=55 is the number of non-crossing, non-nesting set partitions on 3 elements with 6 possible arc colors.
		

Programs

  • PARI
    Vec((1 - 56*x + 1203*x^2 - 12364*x^3 + 60675*x^4 - 113540*x^5 + x^6) / (1 - 63*x + 1589*x^2 - 20515*x^3 + 142915*x^4 - 509549*x^5 + 727767*x^6 - x^7) + O(x^40)) \\ Colin Barker, Jun 22 2019

Formula

G.f.: (1-56*x+1203*x^2-12364*x^3+60675*x^4-113540*x^5+x^6)/ (1-63*x+1589*x^2-20515*x^3+142915*x^4-509549*x^5+727767*x^6-x^7).
a(n) = 63*a(n-1) - 1589*a(n-2) + 20515*a(n-3) - 142915*a(n-4) + 509549*a(n-5) - 727767*a(n-6) + a(n-7) for n>6. - Colin Barker, Jun 22 2019

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

Author

Lily Yen, Apr 25 2013

Keywords

Examples

			For n=3, a(3)=193 is the number of non-crossing, non-nesting, 4-colored set partitions on 4 elements.
		

Programs

  • Mathematica
    LinearRecurrence[{25, -218, 782, -973, 1}, {1, 5, 29, 193, 1441}, 25] (* Paolo Xausa, Feb 06 2024 *)

Formula

G.f.: (1-20*x+122*x^2-224*x^3+x^4)/(1-25*x +218*x^2-782*x^3+973*x^4-x^5).

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

Author

Lily Yen, Apr 24 2013

Keywords

Examples

			a(3) = 103 is the number of non-crossing, non-nesting, 3-colored set partitions on {1,2,3,4}.
		

Programs

  • GAP
    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
    
  • Magma
    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
  • Maple
    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
  • Mathematica
    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 *)
  • PARI
    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
    

Formula

G.f.: (1 - 10*x + 22*x^2 - x^3)/(1 - 14*x + 59*x^2 - 74*x^3 + x^4).
a(n) = 14*a(n-1) -59*a(n-2) +74*a(n-3) -a(n-4), with a(0) = 1, a(1) = 4, a(2) = 19 and a(3) = 103. - Muniru A Asiru, Dec 18 2018

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

Author

Lily Yen, Apr 24 2013

Keywords

Examples

			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.
		

Programs

  • Mathematica
    Join[{1}, LinearRecurrence[{20, -108, 144}, {3, 18, 144}, 20]] (* Jean-François Alcover, Jul 22 2018 *)
  • PARI
    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

Formula

G.f.: (1-17*x+66*x^2-36*x^3)/((1-2*x)*(1-6*x)*(1-12*x)).
a(n) = 9*2^n/20 +6^n/4 +12^n/20, n>0. - R. J. Mathar, Jun 11 2019

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

Author

Lily Yen, Nov 23 2012

Keywords

Comments

The sequence is generated by a rational function, in particular, a quotient of two determinants.

Examples

			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.
		

Programs

  • PARI
    Vec((1 - 5*x) / (1 - 7*x + 6*x^2 + 4*x^3) + O(x^40)) \\ Colin Barker, Jun 22 2019

Formula

G.f.: (1 - 5*x)/(1 - 7*x + 6*x^2 + 4*x^3).
a(n) = 7*a(n-1) - 6*a(n-2) - 4*a(n-3) for n>2. - Colin Barker, Jun 22 2019

Extensions

Name modified by Lily Yen, Apr 23 2013

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

Author

Lily Yen, Aug 09 2011

Keywords

Comments

Also the number of 3-noncrossing permutations.

Crossrefs

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

Author

Lily Yen, Aug 09 2011

Keywords

Comments

Also the number of 6-noncrossing permutations.

Crossrefs