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 1-6 of 6 results.

A182172 Number A(n,k) of standard Young tableaux of n cells and height <= k; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 2, 1, 0, 1, 1, 2, 3, 1, 0, 1, 1, 2, 4, 6, 1, 0, 1, 1, 2, 4, 9, 10, 1, 0, 1, 1, 2, 4, 10, 21, 20, 1, 0, 1, 1, 2, 4, 10, 25, 51, 35, 1, 0, 1, 1, 2, 4, 10, 26, 70, 127, 70, 1, 0, 1, 1, 2, 4, 10, 26, 75, 196, 323, 126, 1, 0, 1, 1, 2, 4, 10, 26, 76, 225, 588, 835, 252, 1, 0
Offset: 0

Views

Author

Alois P. Heinz, Apr 16 2012

Keywords

Comments

Also the number A(n,k) of standard Young tableaux of n cells and <= k columns.
A(n,k) is also the number of n-length words w over a k-ary alphabet {a1,a2,...,ak} such that for every prefix z of w we have #(z,a1) >= #(z,a2) >= ... >= #(z,ak), where #(z,x) counts the letters x in word z. The A(4,4) = 10 words of length 4 over alphabet {a,b,c,d} are: aaaa, aaab, aaba, abaa, aabb, abab, aabc, abac, abca, abcd.

Examples

			A(4,2) = 6, there are 6 standard Young tableaux of 4 cells and height <= 2:
  +------+  +------+  +---------+  +---------+  +---------+  +------------+
  | 1  3 |  | 1  2 |  | 1  3  4 |  | 1  2  4 |  | 1  2  3 |  | 1  2  3  4 |
  | 2  4 |  | 3  4 |  | 2 .-----+  | 3 .-----+  | 4 .-----+  +------------+
  +------+  +------+  +---+        +---+        +---+
Square array A(n,k) begins:
  1,  1,  1,   1,   1,   1,   1,   1,   1, ...
  0,  1,  1,   1,   1,   1,   1,   1,   1, ...
  0,  1,  2,   2,   2,   2,   2,   2,   2, ...
  0,  1,  3,   4,   4,   4,   4,   4,   4, ...
  0,  1,  6,   9,  10,  10,  10,  10,  10, ...
  0,  1, 10,  21,  25,  26,  26,  26,  26, ...
  0,  1, 20,  51,  70,  75,  76,  76,  76, ...
  0,  1, 35, 127, 196, 225, 231, 232, 232, ...
  0,  1, 70, 323, 588, 715, 756, 763, 764, ...
		

Crossrefs

Main diagonal gives A000085.
A(2n,n) gives A293128.

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:= proc(n, i, l) option remember;
          `if`(n=0, h(l), `if`(i<1, 0, `if`(i=1, h([l[], 1$n]),
            g(n, i-1, l) +`if`(i>n, 0, g(n-i, i, [l[], i])))))
        end:
    A:= (n, k)-> g(n, k, []):
    seq(seq(A(n, d-n), n=0..d), d=0..15);
  • Mathematica
    h[l_List] := Module[{n = Length[l]}, Sum[i, {i, l}]!/Product[Product[1 + l[[i]] - j + Sum[If[l[[k]] >= j, 1, 0], {k, i+1, n}], {j, 1, l[[i]]}], {i, 1, n}]];
    g[n_, i_, l_List] := g[n, i, l] = If[n == 0, h[l], If[i < 1, 0, If[i == 1, h[Join[l, Array[1&, n]]], g [n, i-1, l] + If[i > n, 0, g[n-i, i, Append[l, i]]]]]];
    a[n_, k_] := g[n, k, {}];
    Table[Table[a[n, d-n], {n, 0, d}], {d, 0, 15}] // Flatten (* Jean-François Alcover, Dec 06 2013, translated from Maple *)

Formula

Conjecture: A(n,k) ~ k^n/Pi^(k/2) * (k/n)^(k*(k-1)/4) * Product_{j=1..k} Gamma(j/2). - Vaclav Kotesovec, Sep 12 2013

A293740 Number of multisets of nonempty words with a total of n letters over denary alphabet such that within each prefix of a word every letter of the alphabet is at least as frequent as the subsequent alphabet letter.

Original entry on oeis.org

1, 1, 3, 7, 20, 54, 164, 500, 1630, 5472, 19257, 70132, 265845, 1042187, 4233556, 17747898, 76808746, 342105748, 1567582938, 7371055703, 35543320641, 175391546006, 884988267329, 4558168670317, 23945579145172, 128119583103268, 697657759802893, 3861749505389798
Offset: 0

Views

Author

Alois P. Heinz, Oct 15 2017

Keywords

Comments

This sequence differs from A293110 first at n=11.
In general, for k>2, is column k of A293108 asymptotic to c(k) * k^n / n^(k*(k-1)/4), where c(k) are constants dependent only on k. - Vaclav Kotesovec, Dec 19 2020

Crossrefs

Column k=10 of A293108.

Formula

G.f.: Product_{j>=1} 1/(1-x^j)^A212916(j).
a(n) ~ c * 10^n / n^(45/2), where c = 2738042932059662927432072.80048573... - Vaclav Kotesovec, Dec 19 2020

A293749 Number of sets of nonempty words with a total of n letters over denary alphabet such that within each prefix of a word every letter of the alphabet is at least as frequent as the subsequent alphabet letter.

Original entry on oeis.org

1, 1, 2, 6, 15, 45, 136, 430, 1415, 4845, 17235, 63508, 242841, 959746, 3924747, 16551199, 71994097, 322098625, 1481655067, 6990945197, 33812067833, 167294687170, 846131720816, 4367249636291, 22985935628080, 123193976095986, 671862417595209, 3724122166971836
Offset: 0

Views

Author

Alois P. Heinz, Oct 15 2017

Keywords

Crossrefs

Column k=10 of A293112.

Formula

G.f.: Product_{j>=1} (1+x^j)^A212916(j).

A229053 Number of standard Young tableaux of n cells and height <= 11.

Original entry on oeis.org

1, 1, 2, 4, 10, 26, 76, 232, 764, 2620, 9496, 35696, 140151, 568491, 2390311, 10347911, 46191551, 211671999, 996269310, 4801547628, 23695885170, 119481280210, 615372604033, 3232009497979, 17302866542177, 94301143232321, 522945331559246, 2947729723188352
Offset: 0

Views

Author

Vaclav Kotesovec, Sep 12 2013

Keywords

Crossrefs

Cf. A182172, A001405 (k=2), A001006 (k=3), A005817 (k=4), A049401 (k=5), A007579 (k=6), A007578 (k=7), A007580 (k=8), A212915 (k=9), A212916 (k=10).
Column k=11 of A182172.
Cf. A000085.

Programs

  • Mathematica
    RecurrenceTable[{-10395 (-5+n) (-4+n) (-3+n) (-2+n) (-1+n) a[-6+n]-3 (-4+n) (-3+n) (-2+n) (-1+n) (28701+2578 n) a[-5+n]+(-3+n) (-2+n) (-1+n) (331317+74458 n+3319 n^2) a[-4+n]+2 (-2+n) (-1+n) (546120+154023 n+11843 n^2+270 n^3) a[-3+n]-(-1+n) (1857231+1090536 n+149299 n^2+7472 n^3+125 n^4) a[-2+n]+(-2755377-1658520 n-265085 n^2-17752 n^3-535 n^4-6 n^5) a[-1+n]+(10+n) (18+n) (24+n) (28+n) (30+n) a[n]==0,a[1]==1,a[2]==2,a[3]==4,a[4]==10,a[5]==26,a[6]==76}, a, {n, 20}]

Formula

Recurrence: (n+10)*(n+18)*(n+24)*(n+28)*(n+30)*a(n) = (6*n^5 + 535*n^4 + 17752*n^3 + 265085*n^2 + 1658520*n + 2755377)*a(n-1) + (n-1)*(125*n^4 + 7472*n^3 + 149299*n^2 + 1090536*n + 1857231)*a(n-2) - 2*(n-2)*(n-1)*(270*n^3 + 11843*n^2 + 154023*n + 546120)*a(n-3) - (n-3)*(n-2)*(n-1)*(3319*n^2 + 74458*n + 331317)*a(n-4) + 3*(n-4)*(n-3)*(n-2)*(n-1)*(2578*n + 28701)*a(n-5) + 10395*(n-5)*(n-4)*(n-3)*(n-2)*(n-1)*a(n-6).
a(n) ~ 40186125/1024 * 11^(n+55/2)/(Pi^(5/2)*n^(55/2)).
Conjecture: a(n) ~ k^n/Pi^(k/2)*(k/n)^(k*(k-1)/4) * prod(j=1,k,Gamma(j/2)).

A217322 Number of self-inverse permutations in S_n with longest increasing subsequence of length 10.

Original entry on oeis.org

1, 10, 109, 857, 6798, 48007, 338529, 2267425, 15164662, 98964444, 645978814, 4168541022, 26949303558, 173445855265, 1119737108943, 7224864497439, 46800745943134, 303692912870933, 1979556048016406, 12943419575576650, 85040314513698164, 560910092712436079
Offset: 10

Views

Author

Alois P. Heinz, Sep 30 2012

Keywords

Comments

Also the number of Young tableaux with n cells and 10 rows.

Crossrefs

Column k=10 of A047884.

Formula

a(n) = A182172(n,10)-A182172(n,9) = A212916(n)-A212915(n).

A229068 Number of standard Young tableaux of n cells and height <= 12.

Original entry on oeis.org

1, 1, 2, 4, 10, 26, 76, 232, 764, 2620, 9496, 35696, 140152, 568503, 2390466, 10349340, 46204720, 211779200, 997134592, 4808141824, 23745792032, 119848119307, 618058083314, 3251373425356, 17442275104496, 95297400355320, 530067682582320, 2998503402985440
Offset: 0

Views

Author

Vaclav Kotesovec, Sep 12 2013

Keywords

Comments

Conjecture: generally (for tableaux with height <= k), a(n) ~ k^n/Pi^(k/2) * (k/n)^(k*(k-1)/4) * Product_{j=1..k} Gamma(j/2); set k=12 for this sequence.

Crossrefs

Cf. A182172, A001405 (k=2), A001006 (k=3), A005817 (k=4), A049401 (k=5), A007579 (k=6), A007578 (k=7), A007580 (k=8), A212915 (k=9), A212916 (k=10), A229053 (k=11).
Column k=12 of A182172.

Programs

  • Mathematica
    RecurrenceTable[{-147456 (-5+n) (-4+n) (-3+n) (-2+n) (-1+n) (12+n) a[-6+n]-110592 (-4+n) (-3+n) (-2+n) (-1+n) (29+2 n) a[-5+n]+256 (-3+n) (-2+n) (-1+n) (121272+32786 n+2343 n^2+49 n^3) a[-4+n]+128 (-2+n) (-1+n) (438597+90321 n+5391 n^2+98 n^3) a[-3+n]-16 (-1+n) (8718630+5347213 n+804616 n^2+49754 n^3+1372 n^4+14 n^5) a[-2+n]-8 (27335490+10162354 n+1206473 n^2+63328 n^3+1533 n^4+14 n^5) a[-1+n]+(11+n) (20+n) (27+n) (32+n) (35+n) (36+n) a[n]==0, a[1]==1, a[2]==2, a[3]==4, a[4]==10, a[5]==26, a[6]==76}, a, {n, 20}]

Formula

Recurrence: (n+11)*(n+20)*(n+27)*(n+32)*(n+35)*(n+36)*a(n) = 8*(14*n^5 + 1533*n^4 + 63328*n^3 + 1206473*n^2 + 10162354*n + 27335490)*a(n-1) + 16*(n-1)*(14*n^5 + 1372*n^4 + 49754*n^3 + 804616*n^2 + 5347213*n + 8718630)*a(n-2) - 128*(n-2)*(n-1)*(98*n^3 + 5391*n^2 + 90321*n + 438597)*a(n-3) - 256*(n-3)*(n-2)*(n-1)*(49*n^3 + 2343*n^2 + 32786*n + 121272)*a(n-4) + 110592*(n-4)*(n-3)*(n-2)*(n-1)*(2*n + 29)*a(n-5) + 147456*(n-5)*(n-4)*(n-3)*(n-2)*(n-1)*(n+12)*a(n-6).
a(n) ~ 602791875/128 * 12^(n+33)/(Pi^3*n^33).
Showing 1-6 of 6 results.