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.

Previous Showing 11-15 of 15 results.

A096956 Pascal (1,6) triangle.

Original entry on oeis.org

6, 1, 6, 1, 7, 6, 1, 8, 13, 6, 1, 9, 21, 19, 6, 1, 10, 30, 40, 25, 6, 1, 11, 40, 70, 65, 31, 6, 1, 12, 51, 110, 135, 96, 37, 6, 1, 13, 63, 161, 245, 231, 133, 43, 6, 1, 14, 76, 224, 406, 476, 364, 176, 49, 6, 1, 15, 90, 300, 630, 882, 840, 540, 225, 55, 6, 1, 16, 105, 390, 930
Offset: 0

Views

Author

Wolfdieter Lang, Aug 13 2004

Keywords

Comments

Except for the first row this is the row reversed (6,1)-Pascal triangle A093563.
This is the sixth member, q=6, in the family of (1,q) Pascal triangles: A007318 (Pascal (q=1)), A029635 (q=2) (but with a(0,0)=2, not 1), A095660 (q=3), A095666 (q=4), A096940 (q=5).
This is an example of a Riordan triangle (see A053121 for a comment and the 1991 Shapiro et al. reference on the Riordan group) with o.g.f. of column no. m of the type g(x)*(x*f(x))^m with f(0)=1. Therefore the o.g.f. for the row polynomials p(n,x):=Sum_{m=0..n} a(n,m)*x^m is G(z,x)=g(z)/(1-x*z*f(z)). Here: g(x)=(6-5*x)/(1-x), f(x)=1/(1-x), hence G(z,x)=(6-5*z)/(1-(1+x)*z).
The SW-NE diagonals give Sum_{k=0..ceiling((n-1)/2)} a(n-1-k,k) = A022097(n-2), n >= 2, with n=1 value 6. Observation by Paul Barry, Apr 29 2004. Proof via recursion relations and comparison of inputs.

Examples

			Triangle begins:
  [0]  6;
  [1]  1,  6;
  [2]  1,  7,  6;
  [3]  1,  8, 13,  6;
  [4]  1,  9, 21, 19,  6;
  [5]  1, 10, 30, 40, 25,  6;
  ...
		

Crossrefs

Row sums: A005009(n-1), n>=1, 6 if n=0; g.f.: (6-5*x)/(1-2*x). Alternating row sums are [6, -5, followed by 0's].
Column sequences (without leading zeros) give for m=1..9, with n >= 0: A000027(n+6), A056115, A096957-9, A097297-A097300.

Programs

  • Maple
    a(n,k):=piecewise(n=0,6,0Mircea Merca, Apr 08 2012
  • Mathematica
    A096956[n_, k_] := If[n == k, 6, (5*k/n + 1)*Binomial[n, k]];
    Table[A096956[n, k], {n, 0, 12}, {k, 0, n}] (* Paolo Xausa, Apr 14 2025 *)

Formula

Recursion: a(n,m)=0 if m > n, a(0,0) = 6; a(n,0) = 1 if n >= 1; a(n,m) = a(n-1, m) + a(n-1, m-1).
G.f. column m (without leading zeros): (6-5*x)/(1-x)^(m+1), m >= 0.
a(n,k) = (1+5*k/n)*binomial(n,k), for n > 0. - Mircea Merca, Apr 08 2012

A051843 Partial sums of A002419.

Original entry on oeis.org

0, 1, 11, 51, 161, 406, 882, 1722, 3102, 5247, 8437, 13013, 19383, 28028, 39508, 54468, 73644, 97869, 128079, 165319, 210749, 265650, 331430, 409630, 501930, 610155, 736281, 882441, 1050931, 1244216, 1464936, 1715912, 2000152, 2320857, 2681427
Offset: 0

Views

Author

Barry E. Williams, Dec 13 1999

Keywords

Comments

5-dimensional form of octagonal-based pyramidal numbers. - Derek I. Thomas (dithom02(AT)louisville.edu), Jun 30 2007
Convolution of triangular numbers (A000217) and octagonal numbers (A000567). [Bruno Berselli, Jul 21 2015]
Also the number of 4-cycles in the (n+2)-triangular honeycomb bishop graph. - Eric W. Weisstein, Aug 10 2017

References

  • A. H. Beiler, Recreations in the Theory of Numbers, Dover, N.Y., 1964, pp. 194-196.
  • H. J. Ryser, Combinatorial Mathematics, Carus Mathematical Monographs No. 14, John Wiley and Sons, 1963, pp. 1-8.

Crossrefs

Cf. A093563 ((6, 1) Pascal, column m=5).
Cf. A034827 (3-cycles in the triangular honeycomb bishop graph), A290775 (5-cycles), A290779 (6-cycles).

Programs

  • Mathematica
    Join[{0}, Accumulate[LinearRecurrence[{5, -10, 10, -5, 1},{1, 10, 40, 110, 245}, 40]]] (* Harvey P. Dale, Nov 30 2014 *)
    LinearRecurrence[{6, -15, 20, -15, 6, -1}, {0, 1, 11, 51, 161, 406}, 40] (* Harvey P. Dale, Nov 30 2014 *)
    Table[(6 n - 1) Binomial[n + 3, 4]/5, {n, 0, 20}] (* Eric W. Weisstein, Aug 10 2017 *)

Formula

a(n) = C(n+3,4) * (6*n-1)/5
G.f.: x*(1+5*x)/(1-x)^6.
a(n) = n*(n+1)*(n+2)*(n+3)*(6n-1)/120. - Derek I. Thomas (dithom02(AT)louisville.edu), Jun 30 2007

Extensions

a(1) corrected by Gael Linder (linder.gael(AT)wanadoo.fr), Oct 31 2007
a(0) prepended by Joerg Arndt, Jun 26 2013

A034265 a(n) = binomial(n+6,6)*(6*n+7)/7.

Original entry on oeis.org

1, 13, 76, 300, 930, 2442, 5676, 12012, 23595, 43615, 76648, 129064, 209508, 329460, 503880, 751944, 1097877, 1571889, 2211220, 3061300, 4177030, 5624190, 7480980, 9839700, 12808575, 16513731, 21101328, 26739856, 33622600, 41970280
Offset: 0

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Author

Keywords

References

  • A. H. Beiler, Recreations in the Theory of Numbers, Dover, N.Y., 1964, pp. 194-196.

Crossrefs

a(n)=f(n, 5) where f is given in A034261.
Partial sums of A027810.
Cf. A093563 ((6, 1) Pascal, column m=7).
Cf. similar sequences listed in A254142.

Programs

  • GAP
    List([0..30], n-> (6*n+7)*Binomial(n+6,6)/7); # G. C. Greubel, Aug 28 2019
  • Magma
    [(6*n+7)*Binomial(n+6,6)/7: n in [0..40]]; // Vincenzo Librandi, Jul 30 2014
    
  • Maple
    seq((6*n+7)*binomial(n+6,6)/7, n=0..30); # G. C. Greubel, Aug 28 2019
  • Mathematica
    Accumulate[Table[(n+1)Binomial[n+5,5],{n,0,30}]] (* or *) LinearRecurrence[{8,-28,56,-70,56,-28,8,-1}, {1,13,76,300,930,2442,5676, 12012}, 30] (* Harvey P. Dale, Jul 29 2014 *)
    CoefficientList[Series[(1+5x)/(1-x)^8, {x,0,40}], x] (* Vincenzo Librandi, Jul 30 2014 *)
  • PARI
    a(n)=(6*n/7+1)*binomial(n+6,6) \\ Charles R Greathouse IV, Oct 07 2015
    
  • Sage
    [(6*n+7)*binomial(n+6,6)/7 for n in (0..30)] # G. C. Greubel, Aug 28 2019
    

Formula

G.f.: (1+5*x)/(1-x)^8.
a(0)=1, a(1)=13, a(2)=76, a(3)=300, a(4)=930, a(5)=2442, a(6)=5676, a(7)=12012, a(n) = 8*a(n-1) -28*a(n-2) +56*a(n-3) -70*a(n-4) +56*a(n-5) -28*a(n-6) +8*a(n-7) -a(n-8). - Harvey P. Dale, Jul 29 2014

Extensions

Corrected and extended by N. J. A. Sloane, Apr 21 2000

A054487 a(n) = (3*n+4)*binomial(n+7, 7)/4.

Original entry on oeis.org

1, 14, 90, 390, 1320, 3762, 9438, 21450, 45045, 88660, 165308, 294372, 503880, 833340, 1337220, 2089164, 3187041, 4758930, 6970150, 10031450, 14208480, 19832670, 27313650, 37153350, 49961925, 66475656, 87576984, 114316840
Offset: 0

Views

Author

Barry E. Williams, May 06 2000

Keywords

References

  • A. H. Beiler, Recreations in the Theory of Numbers, Dover, N.Y., 1964, pp. 122-125, 194-196.

Crossrefs

Cf. A034265.
Cf. A093563 ((6, 1) Pascal, column m=8).

Programs

  • GAP
    List([0..40], n-> (3*n+4)*Binomial(n+7, 7)/4 ); # G. C. Greubel, Jan 19 2020
  • Magma
    [((3*n+4)*Binomial(n+7,7))/4: n in [0..40]]; // Vincenzo Librandi, Jul 30 2014
    
  • Maple
    seq( (3*n+4)*binomial(n+7,7)/4, n=0..40); # G. C. Greubel, Jan 19 2020
  • Mathematica
    CoefficientList[Series[(1+5x)/(1-x)^9, {x,0,40}], x] (* Vincenzo Librandi, Jul 30 2014 *)
    Table[6*Binomial[n+8,8] -5*Binomial[n+7,7], {n,0,40}] (* G. C. Greubel, Jan 19 2020 *)
    LinearRecurrence[{9,-36,84,-126,126,-84,36,-9,1},{1,14,90,390,1320,3762,9438,21450,45045},30] (* Harvey P. Dale, Jul 19 2022 *)
  • PARI
    a(n) = (3*n+4)*binomial(n+7, 7)/4; \\ Michel Marcus, Sep 07 2017
    
  • Sage
    [(3*n+4)*binomial(n+7, 7)/4 for n in (0..40)] # G. C. Greubel, Jan 19 2020
    

Formula

G.f.: (1+5*x)/(1-x)^9.
From G. C. Greubel, Jan 19 2020: (Start)
a(n) = 6*binomial(n+8, 8) - 5*binomial(n+7, 7).
E.g.f.: (20160 +262080*x +635040*x^2 +540960*x^3 +205800*x^4 +38808*x^5 +3724*x^6 +172*x^7 +3*x^8)*exp(x)/20160. (End)
a(n) = 9*a(n-1)-36*a(n-2)+84*a(n-3)-126*a(n-4)+126*a(n-5)-84*a(n-6)+36*a(n-7)-9*a(n-8)+a(n-9). - Wesley Ivan Hurt, Jun 07 2021

Extensions

Corrected and extended by James Sellers, May 10 2000

A055848 Expansion of (1+5*x)/(1-x)^10.

Original entry on oeis.org

1, 15, 105, 495, 1815, 5577, 15015, 36465, 81510, 170170, 335478, 629850, 1133730, 1967070, 3304290, 5393454, 8580495, 13339425, 20309575, 30341025, 44549505, 64382175, 91695825, 128849175, 178811100, 245286756, 332863740, 447180580
Offset: 0

Views

Author

Barry E. Williams, Jun 03 2000

Keywords

References

  • A. H. Beiler, Recreations in the Theory of Numbers, Dover, N.Y., 1964, pp. 194-196.

Crossrefs

Cf. A054487.
Cf. A093563 ((6, 1) Pascal, column m=9). Partial sums of A054487.

Programs

  • Mathematica
    Table[(2n+3)Binomial[n+8,8]/3,{n,0,30}] (* Harvey P. Dale, Aug 20 2011 *)
  • PARI
    Vec((1+5*x)/(1-x)^10 + O(x^100)) \\ Altug Alkan, Mar 13 2016

Formula

a(n)=(2n+3)*C(n+8, 8)/3. G.f.(x)=(1+5x)/(1-x)^10.
Previous Showing 11-15 of 15 results.