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.

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A001455 Number of permutations of length n with longest increasing subsequence of length 4.

Original entry on oeis.org

1, 16, 181, 1821, 17557, 167449, 1604098, 15555398, 153315999, 1538907306, 15743413076, 164161815768, 1744049683213, 18865209953045, 207591285198178, 2321616416280982, 26362085777156567, 303635722412859447, 3544040394934246209, 41881891423602685193
Offset: 4

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Author

Keywords

References

  • J. M. Hammersley, A few seedings of research, in Proc. Sixth Berkeley Sympos. Math. Stat. and Prob., ed. L. M. le Cam et al., Univ. Calif. Press, 1972, Vol. I, pp. 345-394.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Column k=4 of A047874.

Formula

Recurrence: (n-4)*(n+2)^2*(n+3)^2*(n+4)*(225*n^5 - 180*n^4 - 1713*n^3 + 1354*n^2 + 3326*n - 1604)*a(n) = (n+2)^2*(6750*n^9 - 4500*n^8 - 128025*n^7 + 28068*n^6 + 758512*n^5 - 184396*n^4 - 1719825*n^3 + 606292*n^2 + 573428*n - 274224)*a(n-1) - (n-1)*(61425*n^10 - 39915*n^9 - 1118034*n^8 + 644778*n^7 + 5929529*n^6 - 4355935*n^5 - 10322152*n^4 + 7841792*n^3 + 4333856*n^2 - 3087760*n - 58944)*a(n-2) + 2*(n-2)^2*(n-1)*(92250*n^8 - 88875*n^7 - 1380300*n^6 + 1835846*n^5 + 4241004*n^4 - 9250339*n^3 + 4259094*n^2 + 1427720*n - 1155840)*a(n-3) - 576*(n-3)^2*(n-2)^3*(n-1)*(225*n^5 + 945*n^4 - 183*n^3 - 2615*n^2 + 1300*n + 1408)*a(n-4). - Vaclav Kotesovec, Mar 15 2014
a(n) ~ 3 * 2^(4*n+9) / (Pi^(3/2) * n^(15/2)). - Vaclav Kotesovec, Mar 15 2014

Extensions

More terms from Alois P. Heinz, Jul 01 2012
Name of the sequence clarified by Vaclav Kotesovec, Mar 18 2014

A001456 Number of permutations of length n with longest increasing subsequence of length 5.

Original entry on oeis.org

1, 25, 421, 6105, 83029, 1100902, 14516426, 192422979, 2579725656, 35098717902, 485534447114, 6835409506841, 97966603326993, 1429401763567226, 21226755241285022, 320692032888290224, 4926576077469905280, 76913478420068425515, 1219520974164038038455
Offset: 5

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Author

Keywords

References

  • J. M. Hammersley, A few seedings of research, in Proc. Sixth Berkeley Sympos. Math. Stat. and Prob., ed. L. M. le Cam et al., Univ. Calif. Press, 1972, Vol. I, pp. 345-394.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Column k=5 of A047874.

Formula

Recurrence: (n-5)*(n+3)^3*(n+4)^2*(n+6)^2*(11025*n^8 + 25515*n^7 - 286443*n^6 - 161641*n^5 + 2585080*n^4 - 59048*n^3 - 7819612*n^2 + 146328*n + 7254720)*a(n) = (n+3)^2*(606375*n^14 + 6629175*n^13 - 3194685*n^12 - 243068077*n^11 - 448185134*n^10 + 2897169968*n^9 + 6909605819*n^8 - 18854806947*n^7 - 49141228309*n^6 + 52949408689*n^5 + 157003723774*n^4 - 31022236184*n^3 - 177627829824*n^2 - 22499155440*n + 46832450400)*a(n-1) - (n-1)*(11278575*n^15 + 107036370*n^14 - 128493459*n^13 - 3499379232*n^12 - 3757671198*n^11 + 38759610078*n^10 + 60611718946*n^9 - 233170832954*n^8 - 421914005785*n^7 + 715791177016*n^6 + 1483014906497*n^5 - 861954416990*n^4 - 2293879983512*n^3 + 206528474736*n^2 + 1232273843856*n + 13490305056)*a(n-2) + (n-2)^2*(n-1)*(84286125*n^13 + 498481200*n^12 - 2434626540*n^11 - 13242031168*n^10 + 26565838790*n^9 + 116444106688*n^8 - 166166829480*n^7 - 520627558844*n^6 + 548244457053*n^5 + 1265779705376*n^4 - 798189974324*n^3 - 1219994476884*n^2 + 526747368888*n + 238058922240)*a(n-3) - 2*(n-3)^2*(n-2)^2*(n-1)*(116181450*n^11 + 631786995*n^10 - 3196642374*n^9 - 12497984441*n^8 + 40113159004*n^7 + 67582342915*n^6 - 249420026774*n^5 - 74467478051*n^4 + 592968590146*n^3 - 201054848490*n^2 - 142917171372*n - 573108048)*a(n-4) + 14400*(n-4)^2*(n-3)^3*(n-2)^2*(n-1)*(11025*n^8 + 113715*n^7 + 200862*n^6 - 727084*n^5 - 854995*n^4 + 4446427*n^3 + 2445184*n^2 - 7589778*n + 1695924)*a(n-5). - Vaclav Kotesovec, Mar 16 2014
a(n) ~ 9 * 5^(2*n+25/2) / (2^9 * Pi^2 * n^12). - Vaclav Kotesovec, Mar 16 2014

Extensions

More terms from Alois P. Heinz, Jul 01 2012
Name of the sequence clarified by Vaclav Kotesovec, Mar 18 2014

A001457 Number of permutations of length n with longest increasing subsequence of length 6.

Original entry on oeis.org

1, 36, 841, 16465, 296326, 5122877, 87116283, 1477363967, 25191909848, 434119587475, 7583461369373, 134533482045389, 2426299018270338, 44506885647682026, 830512607486659272, 15764082963927084216, 304295666452406076997, 5971518739677370493811
Offset: 6

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Author

Keywords

Comments

In general, for column k of A047874 is a_k(n) ~ (Product_{j=0..k-1} j!) * k^(2*n + k^2/2) / (2^((k-1)*(k+2)/2) * Pi^((k-1)/2) * n^((k^2-1)/2)) [Regev, 1981]. - Vaclav Kotesovec, Mar 18 2014

References

  • J. M. Hammersley, A few seedings of research, in Proc. Sixth Berkeley Sympos. Math. Stat. and Prob., ed. L. M. le Cam et al., Univ. Calif. Press, 1972, Vol. I, pp. 345-394.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Column k=6 of A047874.

Formula

a(n) ~ 5 * 2^(2*n+6) * 3^(2*n+21) / (Pi^(5/2) * n^(35/2)). - Vaclav Kotesovec, Mar 18 2014

Extensions

More terms from Alois P. Heinz, Jul 01 2012
Name of the sequence clarified by Vaclav Kotesovec, Mar 18 2014

A001458 Number of permutations of length n with longest increasing subsequence of length 7.

Original entry on oeis.org

1, 49, 1513, 38281, 874886, 18943343, 399080475, 8312317976, 172912977525, 3615907795025, 76340522760097, 1631788075873114, 35378058306185002, 778860477345867008, 17423197016288134608, 396169070839236609236, 9157097111888617643722, 215143361542096212159897
Offset: 7

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Author

Keywords

Comments

In general, for column k of A047874 is a_k(n) ~ (Product_{j=0..k-1} j!) * k^(2*n + k^2/2) / (2^((k-1)*(k+2)/2) * Pi^((k-1)/2) * n^((k^2-1)/2)) [Regev, 1981]. - Vaclav Kotesovec, Mar 18 2014

References

  • J. M. Hammersley, A few seedings of research, in Proc. Sixth Berkeley Sympos. Math. Stat. and Prob., ed. L. M. le Cam et al., Univ. Calif. Press, 1972, Vol. I, pp. 345-394.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Column k=7 of A047874.

Formula

a(n) ~ 6075 * 7^(2*n+49/2) / (32768 * Pi^3 * n^24). - Vaclav Kotesovec, Mar 18 2014

Extensions

More terms from Alois P. Heinz, Jul 01 2012
Name of the sequence clarified by Vaclav Kotesovec, Mar 18 2014

A126065 Triangle of numbers read by rows: T(n,k) = number of permutations sigma of (1,2,...,n) with n - {length of longest increasing subsequence in sigma} = k (0<=k<=n-1).

Original entry on oeis.org

1, 1, 1, 1, 4, 1, 1, 9, 13, 1, 1, 16, 61, 41, 1, 1, 25, 181, 381, 131, 1, 1, 36, 421, 1821, 2332, 428, 1, 1, 49, 841, 6105, 17557, 14337, 1429, 1, 1, 64, 1513, 16465, 83029, 167449, 89497, 4861, 1, 1, 81, 2521, 38281, 296326, 1100902, 1604098, 569794, 16795, 1
Offset: 1

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Author

N. J. A. Sloane, Mar 01 2007

Keywords

Comments

T(n,k) is the number of permutations in S_n with Ulam distance from the identity equal to k.
Mirror image of triangle in A047874.

Examples

			Triangle T(n,k) begins:
  1;
  1,   1;
  1,   4,    1;
  1,  13,    9,    1;
  1,  41,   61,   16,   1;
  1, 131,  381,  181,  25,  1;
  1, 428, 2332, 1821, 421, 36, 1;
  ...
		

References

  • P. Diaconis, Group Representations in Probability and Statistics, IMS, 1988; see p. 112.
  • See A047874 for further references, etc.

Crossrefs

T(2n,n) gives A267433.

A054676 Numerator of expected length of longest increasing subsequence of a permutation of length n.

Original entry on oeis.org

1, 3, 2, 29, 67, 2261, 499, 7601, 163673, 3146141, 16688347, 232429801, 1220661809, 1475887019, 96968880223, 5041994433457, 25104916552337, 4417388168138681, 279381762131009, 383174447010300497, 24854210193336894641, 2271390683068712389, 8081231165699623062227
Offset: 1

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Author

Eric M. Rains (rains(AT)caltech.edu), Apr 19 2000

Keywords

Examples

			A054676/A054677 = 1/1, 3/2, 2/1, 29/12, 67/24, 2261/720, 499/144, 7601/2016, 163673/40320, 3146141/725760, 16688347/3628800, 232429801/47900160, ... .
		

Crossrefs

Extensions

More terms from Alois P. Heinz, Feb 14 2016

A054677 Denominator of expected length of longest increasing subsequence of a permutation of length n.

Original entry on oeis.org

1, 2, 1, 12, 24, 720, 144, 2016, 40320, 725760, 3628800, 47900160, 239500800, 276756480, 17435658240, 871782912000, 4184557977600, 711374856192000, 43553562624000, 57926238289920000, 3649353012264960000, 324386934423552000, 1124000727777607680000
Offset: 1

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Author

Eric M. Rains (rains(AT)caltech.edu), Apr 19 2000

Keywords

Crossrefs

Extensions

More terms from Alois P. Heinz, Feb 14 2016

A141824 Antidiagonals of table A047888 (which counts longest increasing subsequences and pattern avoidances).

Original entry on oeis.org

1, 2, 4, 9, 24, 75, 269, 1095, 5039, 26084, 150356, 952526, 6553011, 48553418, 385693800, 3277413802, 29741002168, 287555932433, 2952769116993, 32079033571080, 367336668735826, 4419518218479215, 55733223965845539, 735448682261126767, 10142738983005750681
Offset: 1

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Author

Alford Arnold, Jul 08 2008

Keywords

Comments

Note that:
A000108 avoids string "123"
A005808 avoids string "1234"
A047889 avoids string "12345"
Note also that the left half and central diagonal of A047888 are partial sums of table A047874.

Examples

			We can write A141824(n) = 1 2 4 9 24 ... because A047888 begins
  1;
  1,  1;
  1,  2,  1;
  1,  5,  2,  1;
  1, 14,  6,  2,  1;
etc.
		

Crossrefs

Cf. A000108 (Catalan numbers), A005808, A047889, A047874.

Extensions

a(12)-a(25) from Alois P. Heinz, Apr 10 2012

A239432 Number of permutations of length n with longest increasing subsequence of length 8.

Original entry on oeis.org

1, 64, 2521, 79861, 2250887, 59367101, 1508071384, 37558353900, 927716186325, 22904111472825, 568209449266202, 14216730315766814, 359666061054003144, 9216708503647774264, 239524408949706575548, 6317740398995612513164, 169207499997274346326579, 4602911809939402715164066
Offset: 8

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Author

Vaclav Kotesovec, Mar 18 2014

Keywords

Comments

In general, for column k of A047874 is a(n) ~ product(j!, j=0..k-1) * k^(2*n+k^2/2) / (2^((k-1)*(k+2)/2) * Pi^((k-1)/2) * n^((k^2-1)/2)) [Regev, 1981].

Crossrefs

Formula

a(n) ~ 1913625 * 2^(6*n+77) / (Pi^(7/2) * n^(63/2)).

A245665 Number of permutations of length n with longest increasing subsequence of length 9.

Original entry on oeis.org

1, 81, 3961, 153341, 5213287, 164060352, 4927007100, 143938455225, 4142847526101, 118504614869214, 3389618010035458, 97376389179852540, 2818543211543628620, 82388635477750176388, 2436180769576352799396, 72958306889459609898731, 2214789502139053994814716
Offset: 9

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Author

Alois P. Heinz, Jul 28 2014

Keywords

Crossrefs

Column k=9 of A047874.

Programs

  • Maple
    h:= proc(l) local n; n:= nops(l); add(i, i=l)! /mul(mul(1+l[i]-j
        +add(`if`(l[k]>=j, 1, 0), k=i+1..n), j=1..l[i]), i=1..n) end:
    g:= (n, i, l)-> `if`(n=0 or i=1, h([l[], 1$n])^2, `if`(i<1, 0,
                    add(g(n-i*j, i-1, [l[], i$j]), j=0..n/i))):
    a:= n-> g(n-9, min(n-9, 9), [9]):
    seq(a(n), n=9..30);
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