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 1-7 of 7 results.

A287316 Square array A(n,k) = (n!)^2 [x^n] BesselI(0, 2*sqrt(x))^k read by antidiagonals.

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 2, 1, 0, 1, 3, 6, 1, 0, 1, 4, 15, 20, 1, 0, 1, 5, 28, 93, 70, 1, 0, 1, 6, 45, 256, 639, 252, 1, 0, 1, 7, 66, 545, 2716, 4653, 924, 1, 0, 1, 8, 91, 996, 7885, 31504, 35169, 3432, 1, 0, 1, 9, 120, 1645, 18306, 127905, 387136, 272835, 12870, 1, 0
Offset: 0

Views

Author

Peter Luschny, May 23 2017

Keywords

Comments

A287314 provide polynomials and A287315 rational functions generating the columns of the array.

Examples

			Arrays start:
k\n| 0  1    2      3         4        5          6           7
---|----------------------------------------------------------------
k=0| 1, 0,   0,      0,       0,       0,         0,          0, ... A000007
k=1| 1, 1,   1,      1,       1,       1,         1,          1, ... A000012
k=2| 1, 2,   6,     20,      70,     252,       924,       3432, ... A000984
k=3| 1, 3,  15,     93,     639,    4653,     35169,     272835, ... A002893
k=4| 1, 4,  28,    256,    2716,   31504,    387136,    4951552, ... A002895
k=5| 1, 5,  45,    545,    7885,  127905,   2241225,   41467725, ... A169714
k=6| 1, 6,  66,    996,   18306,  384156,   8848236,  218040696, ... A169715
k=7| 1, 7,  91,   1645,   36715,  948157,  27210169,  844691407, ...
k=8| 1, 8, 120,   2528,   66424, 2039808,  70283424, 2643158400, ... A385286
k=9| 1, 9, 153,   3681,  111321, 3965409, 159700401, 7071121017, ...
       A000384,A169711, A169712, A169713,                            A033935
		

Crossrefs

Rows: A000007 (k=0), A000012 (k=1), A000984 (k=2), A002893 (k=3), A002895 (k=4), A169714 (k=5), A169715 (k=6), A385286 (k=8).
Columns: A001477(n=1), A000384 (n=2), A169711 (n=3), A169712 (n=4), A169713 (n=5).
Cf. A033935 (diagonal), A287314, A287315, A287318.

Programs

  • Maple
    A287316_row := proc(k, len) local b, ser;
    b := k -> BesselI(0, 2*sqrt(x))^k: ser := series(b(k), x, len);
    seq((i!)^2*coeff(ser,x,i), i=0..len-1) end:
    for k from 0 to 6 do A287316_row(k, 9) od;
    A287316_col := proc(n, len) local k, x;
    sum(z^k/k!^2, k = 0..infinity); series(%^x, z=0, n+1):
    unapply(n!^2*coeff(%, z, n), x); seq(%(j), j=0..len) end:
    for n from 0 to 7 do A287316_col(n, 9) od;
  • Mathematica
    Table[Table[SeriesCoefficient[BesselI[0, 2 Sqrt[x]]^k, {x, 0, n}] (n!)^2, {n, 0, 6}], {k, 0,9}]
  • PARI
    A287316_row(K, N) = {
      my(x='x + O('x^(2*N-1)));
      Vec(serlaplace(serlaplace(substpol(besseli(0,2*x)^K, 'x^2, 'x))));
    };
    N=8; concat([vector(N, n, n==1)], vector(9, k, A287316_row(k, N))) \\ Gheorghe Coserea, Jan 12 2018
    
  • PARI
    {A(n, k) = if(n<0 || k<0, 0, n!^2 * polcoeff(besseli(0, 2*x + x*O(x^(2*n)))^k, 2*n))}; /* Michael Somos, Dec 30 2021 */
    
  • PARI
    A(k, n) = my(x='x+O('x^(n+1))); n!^2*polcoeff(hypergeom([], [1], x)^k, n); \\ Peter Luschny, Jun 24 2025
    
  • Python
    from math import comb
    from functools import lru_cache
    @lru_cache(maxsize=None)
    def A(n,k):
        if k <= 0: return 0**n
        return sum(A(i,k-1)*comb(n,i)**2 for i in range(n+1))
    for k in range(10): print([A(n, k) for n in range(8)])
    # Jeremy Tan, Dec 10 2021

Formula

A(n,k) = A287318(n,k) / binomial(2*n,n).
If a+b=k then A(n,k) = Sum_{i=0..n} A(i,a)*A(n-i,b)*binomial(n,i)^2 (Richmond and Shallit). In particular A(n,k) = Sum_{i=0..n} A(i,k-1)*binomial(n,i)^2. - Jeremy Tan, Dec 10 2021

A245397 A(n,k) is the sum of k-th powers of coefficients in full expansion of (z_1+z_2+...+z_n)^n; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 1, 3, 1, 1, 4, 10, 1, 1, 6, 27, 35, 1, 1, 10, 93, 256, 126, 1, 1, 18, 381, 2716, 3125, 462, 1, 1, 34, 1785, 36628, 127905, 46656, 1716, 1, 1, 66, 9237, 591460, 7120505, 8848236, 823543, 6435, 1, 1, 130, 51033, 11007556, 495872505, 2443835736, 844691407, 16777216, 24310
Offset: 0

Views

Author

Alois P. Heinz, Jul 21 2014

Keywords

Examples

			A(3,2) = 93: (z1+z2+z3)^3 = z1^3 +3*z1^2*z2 +3*z1^2*z3 +3*z1*z2^2 +6*z1*z2*z3 +3*z1*z3^2 +z2^3 +3*z2^2*z3 +3*z2*z3^2 +z3^3 => 1^2+3^2+3^2+3^2+6^2+3^2+1^2+3^2+3^2+1^2 = 93.
Square array A(n,k) begins:
0 :    1,    1,      1,       1,         1,           1, ...
1 :    1,    1,      1,       1,         1,           1, ...
2 :    3,    4,      6,      10,        18,          34, ...
3 :   10,   27,     93,     381,      1785,        9237, ...
4 :   35,  256,   2716,   36628,    591460,    11007556, ...
5 :  126, 3125, 127905, 7120505, 495872505, 41262262505, ...
		

Crossrefs

Columns k=0-10 give: A001700(n-1) for n>0, A000312, A033935, A055733, A055740, A246240, A246241, A246242, A246243, A246244, A246245.
Rows n=0+1, 2 give: A000012, A052548.
Main diagonal gives A245398.

Programs

  • Maple
    b:= proc(n, i, k) option remember; `if`(n=0 or i=1, 1,
          add(b(n-j, i-1, k)*binomial(n, j)^k, j=0..n))
        end:
    A:= (n, k)-> b(n$2, k):
    seq(seq(A(n, d-n), n=0..d), d=0..10);
  • Mathematica
    b[n_, i_, k_] := b[n, i, k] = If[n == 0, 1, If[i<1, 0, Sum[b[n-j, i-1, k] * Binomial[n, j]^(k-1)/j!, {j, 0, n}]]]; A[n_, k_] := n!*b[n, n, k]; Table[ Table[A[n, d-n], {n, 0, d}], {d, 0, 10}] // Flatten (* Jean-François Alcover, Jan 30 2015, after Alois P. Heinz *)

Formula

A(n,k) = [x^n] (n!)^k * (Sum_{j=0..n} x^j/(j!)^k)^n.

A364116 a(n) = [x^n] 1/(1 - x) * Legendre_P(n, (1 + x)/(1 - x))^n for n >= 0.

Original entry on oeis.org

1, 3, 73, 5623, 908001, 251831261, 106898093065, 64439674636863, 52344140654486017, 55113399257643294769, 73004404532578627776801, 118810038754810358401521065, 233027150139808176596750408337, 542098915811219991386976197616441
Offset: 0

Views

Author

Peter Bala, Jul 08 2023

Keywords

Comments

Main diagonal of A364113.
Compare with the two types of Apéry numbers A005258 and A005259, which are related to the Legendre polynomials by A005258(n) = [x^n] 1/(1 - x) * Legendre_P(n, (1 + x)/(1 - x)) and A005259(n) = [x^k] 1/(1 - x) * Legendre_P(n, (1 + x)/(1 - x))^2.
A005258 is the main diagonal of A108625 and A005259 is the main diagonal of A143007.

Crossrefs

Programs

  • Maple
    a(n) := coeff(series( 1/(1-x)* LegendreP(n,(1+x)/(1-x))^n, x, 21), x, n):
    seq(a(n), n = 0..20);
  • Mathematica
    Table[SeriesCoefficient[1/(1 - x) * LegendreP[n, (1 + x)/(1 - x)]^n, {x,0,n}], {n,0,20}] (* Vaclav Kotesovec, Jul 09 2023 *)

Formula

Conjectures:
1) a(p) == 2*p + 1 (mod p^4) for all primes p >= 3 (checked up to p = 101).
More generally, the supercongruence a(p^k) == 2*p^k + 1 (mod p^(3+k)) may hold for all primes p >= 5 and all k >= 1.
2) a(p-1) == 1 (mod p^3) for all primes p >= 5 (checked up to p = 101).
More generally, the supercongruence a(p^k - p^(k-1)) == 1 (mod p^(2+k)) may hold for all primes p >= 5 and all k >= 1.
From Vaclav Kotesovec, Jul 10 2023: (Start)
a(n) ~ c * d^n * n^(2*n - 1/2), where d = 2.102423770105721036432437141524634595160013830317976222331887376263238499... (the same as for A033935) and c = 1.325068544739430738025458046917491360304162175529817456184402029433873399...
a(n) ~ A033935(n) * exp(2*n + 1) / (2*Pi*n).
a(n) ~ A033935(n) * exp(1) * n^(2*n) / n!^2. (End)

A055733 Sum of third powers of coefficients in full expansion of (z1+z2+...+zn)^n.

Original entry on oeis.org

1, 1, 10, 381, 36628, 7120505, 2443835736, 1351396969615, 1127288317316008, 1349611750487720817, 2230372438317527996620, 4930842713588476723120511, 14211567663513739084746570600, 52259895270824126097423028107277, 240736564755509319272061470644316416
Offset: 0

Views

Author

Vladeta Jovovic, Jun 09 2000

Keywords

Crossrefs

Cf. A033935.
Column k=3 of A245397.

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,
          add(b(n-j, i-1)*binomial(n, j)^2/j!, j=0..n)))
        end:
    a:= n-> n!*b(n$2):
    seq(a(n), n=0..20);  # Alois P. Heinz, Jul 21 2014
    A055733 := proc(n) series(hypergeom([],[1,1],z)^n,z=0,n+1): n!^3*coeff(%,z,n) end: seq(A055733(n), n=0..14); # Peter Luschny, May 31 2017
  • Mathematica
    b[n_, i_] := b[n, i] = If[n == 0, 1, If[i<1, 0, Sum[b[n-j, i-1]*Binomial[n, j]^2 / j!, {j, 0, n}]]]; a[n_] := n!*b[n, n]; Table[a[n], {n, 0, 20}] (* Jean-François Alcover, Feb 24 2015, after Alois P. Heinz *)
    Table[SeriesCoefficient[HypergeometricPFQ[{}, {1,1}, x]^n, {x,0,n}] n!^3, {n,0,14}] (* Peter Luschny, May 31 2017 *)

Formula

a(n) is coefficient of x^n in expansion of n!^3*(1+x/1!^3+x^2/2!^3+x^3/3!^3+...+x^n/n!^3)^n.
a(n) ~ c * d^n * (n!)^3 / sqrt(n), where d = 1.74218173246413..., c = 0.5728782413434... . - Vaclav Kotesovec, Aug 20 2014
a(n) = (n!)^3 * [z^n] hypergeom([], [1, 1], z)^n. - Peter Luschny, May 31 2017

Extensions

a(0)=1 inserted by Alois P. Heinz, Jul 21 2014

A303503 a(n) = (2*n)! * [x^(2*n)] BesselI(0,2*x)^n.

Original entry on oeis.org

1, 2, 36, 1860, 190120, 32232060, 8175770064, 2898980908824, 1369263687414480, 830988068906518380, 630109741730668410640, 583773362067938664133512, 648851848280206013365243776, 852146184628067383511375555000, 1305460597778526044143501996708800, 2307324514460203126471248458864413200
Offset: 0

Views

Author

Ilya Gutkovskiy, Apr 25 2018

Keywords

Crossrefs

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(n=0 or i=1, 1,
          add(b(n-j, i-1)*binomial(n, j)^2, j=0..n))
        end:
    a:= n-> (2*n)!*b(n$2)/n!^2:
    seq(a(n), n=0..17);  # Alois P. Heinz, Jan 29 2023
  • Mathematica
    Table[(2 n)! SeriesCoefficient[BesselI[0, 2 x]^n, {x, 0, 2 n}], {n, 0, 15}]

Formula

a(n) = A287318(n,n).
a(n) ~ c * d^n * n^(2*n), where c = 1.72802011936236389522137050964080... and d = 1.1381284656425793765251319541847869000364101065484286935... - Vaclav Kotesovec, Apr 26 2018
a(n) = A000984(n)*A033935(n). - Alois P. Heinz, Jan 30 2023

A336665 a(n) = (n!)^2 * [x^n] 1 / BesselJ(0,2*sqrt(x))^n.

Original entry on oeis.org

1, 1, 10, 255, 12196, 939155, 106161756, 16554165495, 3404986723720, 893137635015219, 290965846152033460, 115256679181251696803, 54552992572663333862400, 30406695393635479756804525, 19712738332895648545008815416, 14707436666152282009334357074335
Offset: 0

Views

Author

Ilya Gutkovskiy, Jul 29 2020

Keywords

Crossrefs

Main diagonal of A340986.

Programs

  • Mathematica
    Table[(n!)^2 SeriesCoefficient[1/BesselJ[0, 2 Sqrt[x]]^n, {x, 0, n}], {n, 0, 15}]
    A287316[n_, k_] := A287316[n, k] = If[n == 0, 1, If[k < 1, 0, Sum[Binomial[n, j]^2 A287316[n - j, k - 1], {j, 0, n}]]]; b[n_, k_] := b[n, k] = If[n == 0, 1, Sum[(-1)^(j + 1) Binomial[n, j]^2 A287316[j, k] b[n - j, k], {j, 1, n}]]; a[n_] := b[n, n]; Table[a[n], {n, 0, 15}]

Formula

a(n) ~ c * d^n * n!^2 / sqrt(n), where d = 3.431031961004073074179854315227049823720211... and c = 0.31156343453490677011135864540173577785263... - Vaclav Kotesovec, May 04 2024

A055740 Sum of fourth powers of coefficients in full expansion of (z1+z2+...+zn)^n.

Original entry on oeis.org

1, 1, 18, 1785, 591460, 495872505, 882463317636, 2956241639184631, 17088644286346128840, 159584255348964655673745, 2286523844910576580400966980, 48220116744252542032928364578451, 1446485887751234540636003724054342864, 59981372975740557234356339667492583487125
Offset: 0

Views

Author

Vladeta Jovovic, Jun 09 2000

Keywords

Crossrefs

Cf. A033935.
Column k=4 of A245397.

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,
          add(b(n-j, i-1)*binomial(n, j)^3/j!, j=0..n)))
        end:
    a:= n-> n!*b(n$2):
    seq(a(n), n=0..20);  # Alois P. Heinz, Jul 21 2014
  • Mathematica
    b[n_, i_] := b[n, i] = If[n == 0, 1, If[i<1, 0, Sum[b[n-j, i-1]*Binomial[n, j]^3 /j!, {j, 0, n}]]]; a[n_] := n!*b[n, n]; Table[a[n], {n, 0, 20}] (* Jean-François Alcover, Feb 24 2015, after Alois P. Heinz *)

Formula

a(n) is coefficient of x^n in expansion of n!^4*(1+x/1!^4+x^2/2!^4+x^3/3!^4+...+x^n/n!^4)^n.
a(n) ~ c * d^n * (n!)^4 / sqrt(n), where d = 1.511958716403..., c = 0.6632048858... . - Vaclav Kotesovec, Aug 20 2014

Extensions

a(0)=1 inserted by Alois P. Heinz, Jul 21 2014
Showing 1-7 of 7 results.