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.

A362587 a(n) = 2^n * A094088(n). Row sums of A362586.

Original entry on oeis.org

1, 2, 28, 968, 62512, 6487712, 987533248, 207257057408, 57359688424192, 20240182500956672, 8869195638810631168, 4725115451770644482048, 3007722163880719988764672, 2254432760608214922012434432, 1965374406868398554356767244288, 1971745067277979562424894483365888
Offset: 0

Views

Author

Peter Luschny, Apr 26 2023

Keywords

Crossrefs

Programs

  • SageMath
    def A362587(n) :
        @cached_function
        def f(n) :
            if n == 0 : return 1
            if n % 2 != 0 : return 0
            return sum(f(k) * binomial(n, k) for k in range(n)[::2])
        return 2^n * f(2 * n)
    print([A362587(n) for n in range(16)])

A362585 Triangle read by rows, T(n, k) = A000670(n) * binomial(n, k).

Original entry on oeis.org

1, 1, 1, 3, 6, 3, 13, 39, 39, 13, 75, 300, 450, 300, 75, 541, 2705, 5410, 5410, 2705, 541, 4683, 28098, 70245, 93660, 70245, 28098, 4683, 47293, 331051, 993153, 1655255, 1655255, 993153, 331051, 47293, 545835, 4366680, 15283380, 30566760, 38208450, 30566760, 15283380, 4366680, 545835
Offset: 0

Views

Author

Peter Luschny, Apr 26 2023

Keywords

Examples

			[0]    1;
[1]    1,     1;
[2]    3,     6,     3;
[3]   13,    39,    39,    13;
[4]   75,   300,   450,   300,    75;
[5]  541,  2705,  5410,  5410,  2705,   541;
[6] 4683, 28098, 70245, 93660, 70245, 28098, 4683;
		

Crossrefs

Family of triangles: A055372 (m=0, Pascal), this sequence (m=1, Fubini), A362586 (m=2, Joffe), A362849 (m=3, A278073).
Cf. A000670 (column 0 and main diagonal), A216794 (row sums).

Programs

  • SageMath
    def TransOrdPart(m, n) -> list[int]:
        @cached_function
        def P(m: int, n: int):
            R = PolynomialRing(ZZ, "x")
            if n == 0: return R(1)
            return R(sum(binomial(m * n, m * k) * P(m, n - k) * x
                     for k in range(1, n + 1)))
        T = P(m, n)
        def C(k) -> int:
            return sum(T[j] * binomial(n, k) for j in range(n + 1))
        return [C(k) for k in range(n+1)]
    def A362585(n) -> list[int]: return TransOrdPart(1, n)
    for n in range(6): print(A362585(n))

A362849 Triangle read by rows, T(n, k) = A243664(n) * binomial(n, k).

Original entry on oeis.org

1, 1, 1, 21, 42, 21, 1849, 5547, 5547, 1849, 426405, 1705620, 2558430, 1705620, 426405, 203374081, 1016870405, 2033740810, 2033740810, 1016870405, 203374081, 173959321557, 1043755929342, 2609389823355, 3479186431140, 2609389823355, 1043755929342, 173959321557
Offset: 0

Views

Author

Peter Luschny, May 05 2023

Keywords

Examples

			[0]         1;
[1]         1,          1;
[2]        21,         42,         21;
[3]      1849,       5547,       5547,       1849;
[4]    426405,    1705620,    2558430,    1705620,     426405;
[5] 203374081, 1016870405, 2033740810, 2033740810, 1016870405, 203374081;
		

Crossrefs

Family of triangles: A055372 (m=0, Pascal), A362585 (m=1, Fubini), A362586 (m=2, Joffe), this sequence (m=3, A278073).
Cf. A243664 (column 0 and main diagonal).

Programs

  • SageMath
    # uses[TransOrdPart from A362585]
    def A362849(n) -> list[int]: return TransOrdPart(3, n)
    for n in range(6): print(A362849(n))
Showing 1-3 of 3 results.