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 1-3 of 3 results.

A327002 a(n) = A018893(n) - A291973(n).

Original entry on oeis.org

0, 0, 0, 10, 2574, 748616, 282846568, 141482705378, 93129791442534, 79703248816409088, 87547852413089111888, 121899005847224540133690, 212656111085108159911203710, 459737640779469178164281972792, 1218867518038879445116138285206008, 3923403293626677106527196012373423122
Offset: 0

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Author

Peter Luschny, Aug 13 2019

Keywords

Crossrefs

Cf. A018893, A291973, row 3 of A327000.

Programs

  • Maple
    CL := (f, x) -> PolynomialTools:-CoefficientList(f, x):
    A327002 := proc(n) local P, Q;
    P := proc(n) option remember; if n = 0 then return 1 fi;
    add(binomial(3*n, 3*k+3)*P(n-k-1)*x, k=0..n-1) end:
    Q := proc(n) option remember; if n = 0 then return 1 fi;
    add(binomial(3*n-1, 3*k)*Q(k)*Q(n-1-k), k=0..n-1) end:
    Q(n) - add(CL(P(n),x)[k+1]/k!, k=0..n) end:
    seq(A327002(n), n=0..15);

A327000 A(n, k) = A309522(n, k) - A327001(n, k) for n >= 0 and k >= 3, square array read by ascending antidiagonals.

Original entry on oeis.org

1, 1, 6, 3, 9, 26, 10, 117, 68, 100, 35, 2574, 4500, 517, 365, 126, 70005, 748616, 199155, 4163, 1302, 462, 2082759, 192426260, 282846568, 10499643, 36180, 4606, 1716, 65061234, 59688349943, 799156187475, 141482705378, 663488532, 341733, 16284
Offset: 0

Views

Author

Peter Luschny, Aug 12 2019

Keywords

Examples

			Array starts:
n\k [  3    4        5            6                 7 ]
[0]    1,   6,       26,          100,              365, ...            [A125107]
[1]    1,   9,       68,          517,              4163, ...           [A048742]
[2]    3,   117,     4500,        199155,           10499643, ...       [A326995]
[3]    10,  2574,    748616,      282846568,        141482705378, ...   [A327002]
[4]    35,  70005,   192426260,   799156187475,     4961959681629275, ...
[5]    126, 2082759, 59688349943, 3097220486457142, 278271624962638244163, ...
   A001700,
		

Crossrefs

Programs

  • Maple
    ListTools:-Flatten([seq(seq(A309522(n-k, k) - A327001(n-k, k), k=3..n), n=3..10)]);

Formula

The columns for k = 0, 1, 2 are suppressed as they are identical 0.
A(0, k) = A000108(k) - A011782(k).
A(1, k) = A000142(k) - A000110(k).
A(2, k) = A002105(k) - A005046(k-1) for k >= 1.
A(3, k) = A018893(k) - A291973(k).
A(4, k) = A326999(k) - A291975(k).

A309522 Generalized Blasius numbers, square array read by ascending antidiagonals, A(n, k) for n, k >= 0.

Original entry on oeis.org

1, 1, 1, 1, 1, 2, 1, 1, 2, 5, 1, 1, 4, 6, 14, 1, 1, 11, 34, 24, 42, 1, 1, 36, 375, 496, 120, 132, 1, 1, 127, 6306, 27897, 11056, 720, 429, 1, 1, 463, 129256, 3156336, 3817137, 349504, 5040, 1430, 1, 1, 1717, 2877883, 514334274, 3501788976, 865874115, 14873104, 40320, 4862
Offset: 0

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Author

Keywords

Comments

The generalized Blasius o.d.e. of order n whose infinite series solution involves row n of this square array appears in Salié (1955). Rows n = 2 and n = 3 of this array appear in Kuba and Panholzer (2014, 2016), who give combinatorial interpretations to the numbers in those two rows.
Eq. (22) in Kuba and Panholzer (2014, p. 23) and Eq. (5) in Kuba and Panholzer (2016, p. 233) are general o.d.e.s for generating infinite sequences of numbers with some combinatorial properties. Even though they bear some similarity to Salié's general o.d.e., it is not clear whether either one can be used to give combinatorial interpretation to the numbers in rows n >= 4 of the current square array.

Examples

			Table A(n,k) (with rows n >= 0 and columns k >= 0) begins as follows:
[0] 1, 1,  2,    5,      14,         42,           132, ...  A000108
[1] 1, 1,  2,    6,      24,        120,           720, ...  A000142
[2] 1, 1,  4,   34,     496,      11056,        349504, ...  A002105
[3] 1, 1, 11,  375,   27897,    3817137,     865874115, ...  A018893
[4] 1, 1, 36, 6306, 3156336, 3501788976, 7425169747776, ...
     A260878|
		

Crossrefs

Rows include A000108, A000142, A002105 (shifted), A018893.
Columns include A260878.
Cf. A256522 (Blasius constant), A260876.

Programs

  • Maple
    A := proc(n, k) option remember; if k = 0 then 1 else
    add(binomial(n*k-1, n*v)*A(n, v)*A(n, k-1-v), v=0..k-1) fi end:
    seq(seq(A(n-k, k), k=0..n), n=0..9);
  • Mathematica
    A[n_, k_] := A[n, k] = If[k == 0, 1, Sum[Binomial[n*k - 1, n*v]*A[n, v]* A[n, k - 1 - v], {v, 0, k - 1}]];
    Table[A[n - k, k], {n, 0, 9}, {k, 0, n}] // Flatten (* Jean-François Alcover, Sep 26 2019, from Maple *)

Formula

A(n, k) = Sum_{v=0..k-1} binomial(n*k-1, n*v)*A(n, v)*A(n, k-1-v) for k > 0 and A(n, 0) = 1.
A(n, 2) = A260876(n, 2) = binomial(2*n - 1, n) + 1 for n >= 0.
A(n, 3) = A260876(n, 2) + A260876(n, 3) - 1 = (binomial(3*n - 1, 2*n) + 1) * (binomial(2*n - 1, n) + 1) + binomial(3*n - 1, n) for n >= 1.
Showing 1-3 of 3 results.