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.

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A103769 Trinomial transform of central binomial coefficients A001405.

Original entry on oeis.org

1, 4, 21, 123, 757, 4788, 30817, 200784, 1320093, 8740284, 58193673, 389233287, 2613338091, 17602627006, 118892784555, 804951501469, 5461228061541, 37120212399708, 252720891884473, 1723088114793535, 11763751150648785
Offset: 0

Views

Author

Paul Barry, Feb 15 2005

Keywords

Crossrefs

Cf. A082760.

Programs

  • Mathematica
    CoefficientList[Series[((3*x+1-(21*x^2-10*x+1)^(1/2))/(2*x*(3*x-4)*(7*x-1)))^(1/2), {x, 0, 20}], x] (* Vaclav Kotesovec, Oct 24 2012 *)

Formula

a(n) = sum_{k=0..2n} T(n,k)*C(k,floor(k/2)), where T(n,k) is given by A027907.
a(n) = sum_{k=0..n} sum_{j=0..n} C(n,j)*C(j,k)*C(j+k,floor((j+k)/2)).
G.f.: ((3*x+1-(21*x^2-10*x+1)^(1/2))/(2*x*(3*x-4)*(7*x-1)))^(1/2). - Mark van Hoeij, Nov 16 2011
Conjecture: n*(2n+1)*a(n) +2(-61n^2+57n-20)*a(n-1) +3*(205n^2-523*n+346) * a(n-2) -72*(n-2)*(16n-33)*a(n-3) +567*(n-2)*(n-3)*a(n-4)=0. - R. J. Mathar, Dec 14 2011
a(n) ~ 7^(n+1/2)/sqrt(5*Pi*n). - Vaclav Kotesovec, Oct 24 2012

A134184 A transform of the central binomial coefficients A001405.

Original entry on oeis.org

1, 1, 3, 7, 17, 43, 109, 279, 721, 1871, 4881, 12783, 33585, 88495, 233745, 618719, 1640833, 4358719, 11595841, 30890751, 82391297, 219995007, 588004737, 1573072383, 4211960065, 11286490879, 30265474305
Offset: 0

Views

Author

Paul Barry, Oct 11 2007

Keywords

Comments

Hankel transform is A134185.

Formula

G.f.: g(x(1+x)) where g(x) is the g.f. of A001405; a(n)=sum{k=0..n, binomial(k,n-k)*binomial(k,floor(k/2))}; a(n)=sum{k=0..floor(n/2), binomial(n-k,k)*binomial(n-k,floor((n-k)/2))};

A134185 Hankel transform of a transform of the central binomial coefficients A001405.

Original entry on oeis.org

1, 2, 0, -8, -32, -256, 0, 16384, 262144, 8388608, 0, -8589934592, -549755813888, -70368744177664, 0, 1152921504606846976, 295147905179352825856, 151115727451828646838272, 0, -39614081257132168796771975168
Offset: 0

Views

Author

Paul Barry, Oct 11 2007

Keywords

Comments

Hankel transform of A134184.

Crossrefs

Formula

a(n) = ((1/2 - 1/sqrt(2))*cos(3*Pi*n/4) + (1/2 + 1/sqrt(2))*cos(Pi*n/4))*2^ceiling(binomial(n+1,2)/2).

A161240 Number of partitions of n into central binomial coefficients A001405.

Original entry on oeis.org

1, 2, 3, 4, 5, 8, 9, 12, 15, 19, 22, 29, 33, 40, 47, 56, 63, 76, 85, 100, 113, 131, 146, 169, 187, 214, 237, 268, 295, 334, 365, 410, 449, 499, 545, 606, 657, 727, 789, 868, 940, 1033, 1114, 1219, 1315, 1433, 1542, 1678, 1800, 1954, 2095, 2266, 2426, 2619, 2798
Offset: 1

Views

Author

R. H. Hardin, Jun 06 2009

Keywords

Examples

			a(6)=8 because we have 6, 33, 321, 3111, 222, 2211, 21111, and 111111. - _Emeric Deutsch_, Jun 21 2009
		

Programs

  • Maple
    g := 1/(product(1-x^binomial(j, floor((1/2)*j)), j = 1 .. 15)): gser := series(g, x = 0, 63): seq(coeff(gser, x, n), n = 1 .. 55); # Emeric Deutsch, Jun 21 2009

Formula

G.f.: 1/Product_{j>=1} (1 - x*binomial(j, floor(j/2))). - Emeric Deutsch, Jun 21 2009

A161241 Number of partitions of n into central binomial coefficients A001405 where every part appears at least 2 times.

Original entry on oeis.org

0, 1, 1, 2, 1, 4, 2, 5, 5, 7, 6, 12, 9, 14, 15, 19, 18, 28, 24, 34, 35, 43, 42, 59, 53, 70, 72, 86, 86, 112, 105, 132, 136, 158, 160, 198, 191, 231, 238, 273, 277, 332, 326, 384, 394, 447, 455, 532, 529, 610, 626, 703, 717, 821, 824, 934, 959, 1066, 1089, 1230, 1240, 1388
Offset: 1

Views

Author

R. H. Hardin, Jun 06 2009

Keywords

Crossrefs

Cf. A001405.

A161242 Number of partitions of n into central binomial coefficients A001405 where every part appears at least 3 times.

Original entry on oeis.org

0, 0, 1, 1, 1, 2, 1, 2, 3, 3, 3, 6, 5, 6, 9, 8, 9, 14, 12, 14, 19, 19, 21, 28, 26, 30, 37, 38, 41, 53, 50, 56, 68, 69, 74, 91, 88, 98, 115, 118, 125, 150, 149, 163, 188, 192, 204, 239, 239, 260, 293, 303, 322, 367, 372, 400, 444, 462, 487, 548, 557, 597, 657, 682, 718, 795, 812, 868
Offset: 1

Views

Author

R. H. Hardin, Jun 06 2009

Keywords

Crossrefs

Cf. A001405.

A161243 Number of partitions of n into central binomial coefficients A001405 where every part appears at least 4 times.

Original entry on oeis.org

0, 0, 0, 1, 1, 1, 1, 2, 1, 2, 1, 4, 2, 4, 4, 6, 5, 8, 7, 10, 9, 12, 11, 16, 14, 18, 18, 23, 23, 29, 28, 34, 34, 41, 41, 51, 49, 58, 59, 70, 69, 83, 81, 95, 96, 110, 110, 130, 127, 147, 147, 169, 168, 196, 195, 221, 224, 253, 254, 291, 289, 326, 330, 370, 374, 420, 423, 471, 480, 531, 537
Offset: 1

Views

Author

R. H. Hardin, Jun 06 2009

Keywords

Crossrefs

Cf. A001405.

A161244 Number of partitions of n into central binomial coefficients A001405 where every part appears at least 5 times.

Original entry on oeis.org

0, 0, 0, 0, 1, 1, 1, 1, 1, 2, 1, 2, 1, 2, 3, 3, 3, 5, 4, 6, 7, 7, 8, 10, 10, 11, 13, 13, 14, 18, 17, 19, 22, 23, 26, 31, 31, 34, 38, 41, 44, 51, 51, 56, 62, 66, 70, 80, 80, 89, 96, 101, 107, 120, 122, 132, 143, 149, 157, 176, 176, 190, 204, 213, 226, 248, 252, 271, 290, 305, 319, 348, 355
Offset: 1

Views

Author

R. H. Hardin Jun 06 2009

Keywords

A161245 Number of partitions of n into central binomial coefficients A001405 where every part appears at least 6 times.

Original entry on oeis.org

0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 4, 2, 4, 4, 5, 4, 8, 6, 8, 9, 10, 9, 14, 11, 14, 15, 16, 15, 22, 18, 22, 24, 26, 26, 35, 32, 37, 40, 43, 44, 55, 52, 59, 62, 67, 68, 83, 79, 89, 93, 100, 101, 122, 116, 129, 135, 144, 145, 172, 165, 182, 190, 202, 202, 236, 226, 249, 259, 275, 276
Offset: 1

Views

Author

R. H. Hardin, Jun 06 2009

Keywords

Crossrefs

Cf. A001405.

A161246 Number of partitions of n into central binomial coefficients A001405 where every part appears at least 7 times.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 2, 3, 3, 3, 5, 4, 5, 6, 7, 7, 9, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 22, 22, 24, 26, 28, 30, 34, 36, 39, 42, 45, 48, 53, 56, 61, 64, 69, 72, 79, 82, 89, 94, 100, 104, 114, 117, 126, 133, 142, 146, 159, 163, 174, 183, 193, 201, 216, 222
Offset: 1

Views

Author

R. H. Hardin, Jun 06 2009

Keywords

Crossrefs

Cf. A001405.
Previous Showing 31-40 of 434 results. Next