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.

A258708 Triangle read by rows: T(i,j) = integer part of binomial(i+j, i-j)/(2*j+1) for i >= 1 and j = 0..i-1.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 3, 3, 1, 1, 5, 7, 4, 1, 1, 7, 14, 12, 5, 1, 1, 9, 25, 30, 18, 6, 1, 1, 12, 42, 66, 55, 26, 7, 1, 1, 15, 66, 132, 143, 91, 35, 8, 1, 1, 18, 99, 245, 334, 273, 140, 45, 9, 1, 1, 22, 143, 429, 715, 728, 476, 204, 57, 10, 1
Offset: 1

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Author

N. J. A. Sloane, Jun 12 2015

Keywords

Comments

In the Loh-Shannon-Horadam paper, Table 3 contains a typo (see Extensions lines).
T(n,k) = round(A258993(n,k)/(2*k+1)). - Reinhard Zumkeller, Jun 22 2015
From Reinhard Zumkeller, Jun 23 2015: (Start)
(using tables 4 and 5 of the Loh-Shannon-Horadam paper, p. 8f).
T(n, n-1) = 1;
T(n, n-2) = n for n > 1;
T(n, n-3) = A000969(n-3) for n > 2;
T(n, n-4) = A000330(n-3) for n > 3;
T(n, n-5) = T(2*n-7, 2) = A000970(n) for n > 4;
T(n, n-6) = A000971(n) for n > 5;
T(n, n-7) = A000972(n) for n > 6;
T(n, n-8) = A000973(n) for n > 7;
T(n, 1) = A001840(n-1) for n > 1;
T(2*n, n) = A001764(n);
T(3*n-1, 1) = A000326(n);
T(3*n, 2*n) = A002294(n);
T(4*n, 3*n) = A002296(n). (End)

Examples

			Triangle T(i, j) (with rows i >= 1 and columns j >= 0) begins as follows:
  1;
  1,  1;
  1,  2,  1;
  1,  3,  3,   1;
  1,  5,  7,   4,   1;
  1,  7, 14,  12,   5,   1;
  1,  9, 25,  30,  18,   6,   1;
  1, 12, 42,  66,  55,  26,   7,  1;
  1, 15, 66, 132, 143,  91,  35,  8, 1;
  1, 18, 99, 245, 334, 273, 140, 45, 9, 1;
  ...
		

Crossrefs

Programs

  • Haskell
    a258708 n k = a258708_tabl !! (n-1) !! k
    a258708_row n = a258708_tabl !! (n-1)
    a258708_tabl = zipWith (zipWith ((round .) . ((/) `on` fromIntegral)))
                           a258993_tabl a158405_tabl
    -- Reinhard Zumkeller, Jun 22 2015, Jun 16 2015

Extensions

Corrected T(8,5) = 26 from Reinhard Zumkeller, Jun 13 2015

A053129 Binomial coefficients C(2*n-6,7).

Original entry on oeis.org

8, 120, 792, 3432, 11440, 31824, 77520, 170544, 346104, 657800, 1184040, 2035800, 3365856, 5379616, 8347680, 12620256, 18643560, 26978328, 38320568, 53524680, 73629072, 99884400, 133784560, 177100560, 231917400, 300674088, 386206920, 491796152, 621216192
Offset: 7

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Keywords

References

  • M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings).

Crossrefs

Programs

Formula

a(n) = binomial(2*n-6, 7) if n >= 7 else 0.
a(n) = -A053123(n,7), n >= 7; a(n) := 0, n=0..6, (eighth column of shifted Chebyshev's S-triangle, decreasing order).
a(n) = 8*A000973(n).
G.f.: (8+56*x+56*x^2+8*x^3)/(1-x)^8.
a(n) = (n-6)*(n-5)*(n-4)*(n-3)*(2*n-11)*(2*n-9)*(2*n-7)/315. - Wesley Ivan Hurt, Mar 25 2020
From Amiram Eldar, Oct 21 2022: (Start)
Sum_{n>=7} 1/a(n) = 777/5 - 224*log(2).
Sum_{n>=7} (-1)^(n+1)/a(n) = 441/10 - 14*Pi. (End)

A059251 A sequence related to numeric partitions and Fermat Coefficients.

Original entry on oeis.org

1, 1, 5, 15, 44, 99, 217, 429, 811, 1430, 2438, 3978, 6312, 9690, 14550, 21318, 30669, 43263, 60115, 82225, 111044, 148005, 195143, 254475, 328759, 420732, 534076, 672452, 840656, 1043460, 1287036, 1577532, 1922745, 2330445, 2810385, 3372291
Offset: 1

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Author

Alford Arnold, Jan 22 2001

Keywords

Comments

The sequences m1^8, m2^4 and 6*m4^2 correspond to eight elements of a finite group of order eight belonging to the appropriate partition class.

Examples

			a(5)= 44 because (1/8)*( 330 + 10 + 12) = 352/8; a(9)= 811 because (1/8)*(6435 + 35 + 18) = 6488/8.
		

Crossrefs

Formula

Let m1^8 = A000580, m2^4 = 1 0 4 0 10 0 20 ... and let m4^2 = 1 0 0 0 2 0 0 0 3 0 0 0 4 ... Then a(n) = (1/8)*(m1^8 + m2^4 + 6*m4^2).
Empirical g.f.: x*(1 - 3*x + 5*x^2 + 3*x^3 - 4*x^4 + 3*x^5 + 5*x^6 - 3*x^7 + x^8) / ((1 - x)^8*(1 + x)^4*(1 + x^2)^2). - Colin Barker, Mar 30 2017

Extensions

More terms from David Wasserman, Jun 07 2002
Showing 1-3 of 3 results.