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 1-9 of 9 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

A293738 Number of multisets of nonempty words with a total of n letters over octonary 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, 5471, 19246, 70020, 264961, 1035540, 4187725, 17440159, 74817905, 329400093, 1487844185, 6873585346, 32460719143, 156315314070, 767106102127, 3828629444020, 19423438144438, 99998608025751, 522200287437179, 2762351298913471
Offset: 0

Views

Author

Alois P. Heinz, Oct 15 2017

Keywords

Comments

This sequence differs from A293110 first at n=9.

Crossrefs

Column k=8 of A293108.

Programs

  • Maple
    g:= proc(n) option remember; `if`(n<4, [1, 1, 2, 4][n+1],
          ((40*n^3+1084*n^2+8684*n+18480)*g(n-1) +16*(n-1)*
          (5*n^3+107*n^2+610*n+600)*g(n-2) -1024*(n-1)*(n-2)*
          (n+6)*g(n-3) -1024*(n-1)*(n-2)*(n-3)*(n+4)*g(n-4))
           /((n+7)*(n+12)*(n+15)*(n+16)))
        end:
    a:= proc(n) option remember; `if`(n=0, 1, add(add(g(d)
          *d, d=numtheory[divisors](j))*a(n-j), j=1..n)/n)
        end:
    seq(a(n), n=0..35);

Formula

G.f.: Product_{j>=1} 1/(1-x^j)^A007580(j).
a(n) ~ c * 8^n / n^14, where c = 4485962145436.6348123684794... - Vaclav Kotesovec, Dec 19 2020

A293747 Number of sets of nonempty words with a total of n letters over octonary 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, 4844, 17224, 63397, 241968, 953213, 3879822, 16250333, 70050877, 309714232, 1404000641, 6506809837, 30813282963, 148741986670, 731495853897, 3657808596354, 18588011870288, 95841754173073, 501169433939670, 2654344778727646
Offset: 0

Views

Author

Alois P. Heinz, Oct 15 2017

Keywords

Crossrefs

Column k=8 of A293112.

Programs

  • Maple
    g:= proc(n) option remember; `if`(n<4, [1, 1, 2, 4][n+1],
          ((40*n^3+1084*n^2+8684*n+18480)*g(n-1) +16*(n-1)*
          (5*n^3+107*n^2+610*n+600)*g(n-2) -1024*(n-1)*(n-2)*
          (n+6)*g(n-3) -1024*(n-1)*(n-2)*(n-3)*(n+4)*g(n-4))
           /((n+7)*(n+12)*(n+15)*(n+16)))
        end:
    b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,
          add(b(n-i*j, i-1)*binomial(g(i), j), j=0..n/i)))
        end:
    a:= n-> b(n$2):
    seq(a(n), n=0..35);
  • Mathematica
    h[l_] := Function[n, Total[l]!/Product[Product[1 + l[[i]] - j + Sum[If[ l[[k]] < j, 0, 1], {k, i + 1, n}], {j, 1, l[[i]]}], {i, 1, n}]][ Length[l]];
    g[n_, i_, l_] := g[n, i, l] = If[n == 0, h[l], If[i < 1, 0, If[i == 1, h[Join[l, Table[1, n]]], g[n, i - 1, l] + If[i > n, 0, g[n - i, i, Append[l, i]]]]]];
    b[n_, i_, k_] := b[n, i, k] = If[n == 0, 1, If[i < 1, 0, Sum[b[n - i*j, i - 1, k]*Binomial[g[i, k, {}], j], {j, 0, n/i}]]];
    a[n_] := b[n, n, 8];
    Table[a[n], {n, 0, 35}] (* Jean-François Alcover, Jun 06 2018, using code from A293112 *)

Formula

G.f.: Product_{j>=1} (1+x^j)^A007580(j).

A049400 Partial sums of rows of A047884. Young Tableaux by height.

Original entry on oeis.org

1, 1, 2, 1, 3, 4, 1, 6, 9, 10, 1, 10, 21, 25, 26, 1, 20, 51, 70, 75, 76, 1, 35, 127, 196, 225, 231, 232, 1, 70, 323, 588, 715, 756, 763, 764, 1, 126, 835, 1764, 2347, 2556, 2611, 2619, 2620, 1, 252, 2188, 5544, 7990, 9096, 9415, 9486, 9495, 9496, 1, 462, 5798, 17424, 27908, 33231, 35135, 35596
Offset: 1

Views

Author

Keywords

Examples

			1;
1,  2;
1,  3,   4;
1,  6,   9,  10;
1, 10,  21,  25,  26;
1, 20,  51,  70,  75,  76;
1, 35, 127, 196, 225, 231, 232;
1, 70, 323, 588, 715, 756, 763, 764;
		

Crossrefs

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:
    T:= (n, k)-> g(n, k, []):
    seq(seq(T(n, k), k=1..n), n=1..12); # Alois P. Heinz, Apr 16 2012
  • Mathematica
    Accumulate /@ Table[ Plus @@ NumberOfTableaux /@ Reverse /@ Union[ Sort /@ (Compositions[n - m, m] + 1)], {n, 1, 12}, {m, 1, n}] // Flatten (* Jean-François Alcover, Jan 29 2013, after Mathematica program for A047884 *)

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)).

A217321 Number of self-inverse permutations in S_n with longest increasing subsequence of length 9.

Original entry on oeis.org

1, 9, 89, 639, 4655, 30330, 198148, 1233743, 7694099, 46938514, 287070944, 1738940782, 10570927022, 64059763010, 389873574058, 2373799261605, 14522526860316, 89060416668016, 548932942208392, 3395326330414774, 21109553761623110, 131785019270029876
Offset: 9

Views

Author

Alois P. Heinz, Sep 30 2012

Keywords

Comments

Also the number of Young tableaux with n cells and 9 rows.

Crossrefs

Column k=9 of A047884.

Formula

a(n) = A182172(n,9)-A182172(n,8) = A212915(n)-A007580(n).

A217328 Number of self-inverse permutations in S_n with longest increasing subsequence of length 8.

Original entry on oeis.org

1, 8, 71, 461, 3057, 18225, 109446, 628652, 3628517, 20538209, 116808172, 659078098, 3737763884, 21153403644, 120354760098, 685455514294, 3925104616303, 22535893275064, 130089736567064, 753604985013128, 4388755545268226, 25660332309744370, 150802834643569274
Offset: 8

Views

Author

Alois P. Heinz, Sep 30 2012

Keywords

Comments

Also the number of Young tableaux with n cells and 8 rows.

Examples

			a(8) = 1: 12345678.
a(9) = 8: 123456798, 123456879, 123457689, 123465789, 123546789, 124356789, 132456789, 213456789.
		

Crossrefs

Column k=8 of A047884.

Formula

a(n) = A182172(n,8)-A182172(n,7) = A007580(n)-A007578(n).

A218269 Number of standard Young tableaux of n cells and height >= 9.

Original entry on oeis.org

1, 10, 100, 760, 5656, 38416, 257376, 1660416, 10640692, 67100072, 422374352, 2643349180, 16566306380, 103786892840, 652502735152, 4113403313016, 26057914447911, 165824119892086, 1061381766546172, 6832087071296824, 44260892997918920, 288574772339715376
Offset: 9

Views

Author

Alois P. Heinz, Oct 24 2012

Keywords

Comments

Also number of self-inverse permutations in S_n with longest increasing subsequence of length >= 9.

Crossrefs

Column k=9 of A182222.

Programs

  • Maple
    b:= proc(n) b(n):= `if`(n<2, 1, b(n-1) +(n-1)*b(n-2)) end:
    g:= proc(n) option remember; `if`(n<4, [1, 1, 2, 4][n+1],
          ((40*n^3+1084*n^2+8684*n+18480)*g(n-1) +16*(n-1)
          *(5*n^3+107*n^2+610*n+600)*g(n-2) -1024*(n-1)*(n-2)
          *(n+6)*g(n-3) -1024*(n-1)*(n-2)*(n-3)*(n+4)*g(n-4))/
           ((n+7)*(n+12)*(n+15)*(n+16)))
        end:
    a:= n-> b(n) -g(n):
    seq(a(n), n=9..30);

Formula

a(n) = A000085(n) - A007580(n) = A182172(n,n) - A182172(n,8).

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 1-9 of 9 results.