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 1-4 of 4 results.

A053200 Binomial coefficients C(n,k) reduced modulo n, read by rows; T(0,0)=0 by convention.

Original entry on oeis.org

0, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 2, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 3, 2, 3, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 4, 0, 6, 0, 4, 0, 1, 1, 0, 0, 3, 0, 0, 3, 0, 0, 1, 1, 0, 5, 0, 0, 2, 0, 0, 5, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 6, 4, 3, 0, 0, 0, 3, 4, 6, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
Offset: 0

Views

Author

Asher Auel, Dec 12 1999

Keywords

Comments

Pascal's triangle read by rows, where row n is read mod n.
A number n is a prime if and only if (1+x)^n == 1+x^n (mod n), i.e., if and only if the n-th row is 1,0,0,...,0,1. This result underlies the proof of Agrawal, Kayal and Saxena that there is a polynomial-time algorithm for primality testing. - N. J. A. Sloane, Feb 20 2004
A020475(n) = number of zeros in n-th row, for n > 0. - Reinhard Zumkeller, Jan 01 2013

Examples

			Row 4 = 1 mod 4, 4 mod 4, 6 mod 4, 4 mod 4, 1 mod 4 = 1, 0, 2, 0, 1.
Triangle begins:
  0;
  0,0;
  1,0,1;
  1,0,0,1;
  1,0,2,0,1;
  1,0,0,0,0,1;
  1,0,3,2,3,0,1;
  1,0,0,0,0,0,0,1;
  1,0,4,0,6,0,4,0,1;
  1,0,0,3,0,0,3,0,0,1;
  1,0,5,0,0,2,0,0,5,0,1;
  1,0,0,0,0,0,0,0,0,0,0,1;
  1,0,6,4,3,0,0,0,3,4,6,0,1;
  1,0,0,0,0,0,0,0,0,0,0,0,0,1;
		

Crossrefs

Row sums give A053204. Cf. A053201, A053202, A053203, A007318 (Pascal's triangle).
Cf. also A092241.
Cf. A053214 (central terms, apart from initial 1).

Programs

  • Haskell
    a053200 n k = a053200_tabl !! n !! k
    a053200_row n = a053200_tabl !! n
    a053200_tabl = [0] : zipWith (map . flip mod) [1..] (tail a007318_tabl)
    -- Reinhard Zumkeller, Jul 10 2015, Jan 01 2013
    
  • Maple
    f := n -> seriestolist( series( expand( (1+x)^n ) mod n, x, n+1)); # N. J. A. Sloane
  • Mathematica
    Flatten[Join[{0},Table[Mod[Binomial[n,Range[0,n]],n],{n,20}]]] (* Harvey P. Dale, Apr 29 2013 *)
  • PARI
    T(n,k)=if(n, binomial(n,k)%n, 0) \\ Charles R Greathouse IV, Feb 07 2017

Extensions

Corrected by T. D. Noe, Feb 08 2008
Edited by N. J. A. Sloane, Aug 29 2008 at the suggestion of R. J. Mathar

A053205 Row sums of A053201.

Original entry on oeis.org

0, 0, 2, 0, 8, 0, 14, 6, 12, 0, 26, 0, 44, 36, 62, 0, 44, 0, 74, 48, 68, 0, 134, 30, 80, 78, 154, 0, 242, 0, 254, 72, 36, 86, 170, 0, 116, 84, 254, 0, 440, 0, 322, 330, 324, 0, 590, 126, 272, 414, 430, 0, 674, 96, 646, 120, 408, 0, 794, 0, 932, 384, 958, 290, 524, 0
Offset: 2

Views

Author

Asher Auel, Dec 12 1999

Keywords

Examples

			a(6) = 0 + 3 + 2 + 3 + 0 = 8.
		

Crossrefs

Programs

Formula

a(n) = A053204(n) - 2.
a(prime(n)) = 0.

Extensions

Corrected and extended by James Sellers, Dec 13 1999

A090249 a(n) = 28a(n-1) - a(n-2), starting with a(0) = 2 and a(1) = 28.

Original entry on oeis.org

2, 28, 782, 21868, 611522, 17100748, 478209422, 13372763068, 373959156482, 10457483618428, 292435582159502, 8177738816847628, 228684251289574082, 6394981297291226668, 178830792072864772622, 5000867196742922406748
Offset: 0

Views

Author

Nikolay V. Kosinov (kosinov(AT)unitron.com.ua), Jan 24 2004

Keywords

Comments

a(n+1)/a(n) converges to (14+sqrt(195)) =27.96424004... Lim a(n)/a(n+1) as n approaches infinity = 0.03575995... = 1/(14+sqrt(195)) = (14-sqrt(195)). Lim a(n+1)/a(n) as n approaches infinity = 27.96424004... = (14+sqrt(195)) = 1/(14-sqrt(195)). Lim a(n)/a(n+1) = 28 - Lim a(n+1)/a(n).

Examples

			a(4) = 611522 = 28a(3) - a(2) = 28*21868 - 782 =(14+sqrt(195))^4 + (14-sqrt(195))^4 =611521.999998364 + 0.000001635 =611522.
		

Crossrefs

Programs

  • Mathematica
    a[0] = 2; a[1] = 28; a[n_] := 28a[n - 1] - a[n - 2]; Table[ a[n], {n, 0, 15}] (* Robert G. Wilson v, Jan 30 2004 *)
    LinearRecurrence[{28,-1},{2,28},20] (* or *) CoefficientList[ Series[ (2-28x)/(x^2-28x+1),{x,0,20}],x] (* Harvey P. Dale, Jun 25 2011 *)
  • Sage
    [lucas_number2(n,28,1) for n in range(0,16)] # Zerinvary Lajos, Jun 27 2008

Formula

a(n) = 28a(n-1) - a(n-2), starting with a(0) = 2 and a(1) = 28. a(n) = (14+sqrt(195))^n + (14-sqrt(195))^n. (a(n))^2 =a(2n)+2.
G.f.: (2-28*x)/(1-28*x+x^2). - Philippe Deléham, Nov 02 2008

Extensions

More terms from Robert G. Wilson v, Jan 30 2004

A053206 Row sums of A053203.

Original entry on oeis.org

2, 0, 6, 6, 2, 0, 14, 0, 30, 36, 46, 0, 26, 0, 54, 48, 46, 0, 110, 30, 54, 78, 126, 0, 212, 0, 222, 72, 2, 86, 134, 0, 78, 84, 214, 0, 398, 0, 278, 330, 278, 0, 542, 126, 222, 414, 378, 0, 620, 96, 590, 120, 350, 0, 734, 0, 870, 384, 894, 290, 458, 0, 150, 558, 742, 0, 1142
Offset: 6

Views

Author

Asher Auel, Dec 12 1999

Keywords

Examples

			a(6) = 3 + 0 + 0 + 3 = 6.
		

Crossrefs

Programs

Formula

a(n) = A053204(n) - n*((n+1) mod 2) - 2.
a(prime(n)) = 0, where prime(n) is the n-th prime.

Extensions

Corrected and extended by James Sellers, Dec 13 1999
Showing 1-4 of 4 results.