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 1-5 of 5 results.

A050484 Partial sums of A051946.

Original entry on oeis.org

1, 12, 68, 264, 810, 2112, 4884, 10296, 20163, 37180, 65208, 109616, 177684, 279072, 426360, 635664, 927333, 1326732, 1865116, 2580600, 3519230, 4736160, 6296940, 8278920, 10772775, 13884156, 17735472, 22467808, 28242984, 35245760
Offset: 0

Views

Author

Barry E. Williams, Dec 26 1999

Keywords

References

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

Crossrefs

Cf. A051946, A093562 ((5, 1) Pascal, column m=7).

Programs

  • Magma
    [((5*n+7)*Binomial(n+6,6))/7: n in [0..60]]; // Vincenzo Librandi, Jul 30 2014
    
  • Mathematica
    CoefficientList[Series[(1 + 4 x)/(1 - x)^8, {x, 0, 50}], x] (* Vincenzo Librandi, Jul 30 2014 *)
    Accumulate[CoefficientList[Series[(1+4x)/(1-x)^7,{x,0,40}],x]] (* or *) LinearRecurrence[{8,-28,56,-70,56,-28,8,-1},{1,12,68,264,810,2112,4884,10296},30] (* Harvey P. Dale, Aug 21 2020 *)
  • PARI
    a(n)=binomial(n+6, 6)*(5*n+7)/7 \\ Charles R Greathouse IV, Oct 07 2015

Formula

a(n) = C(n+6, 6)*(5n+7)/7.
G.f.: (1+4*x)/(1-x)^8.

A093562 (5,1) Pascal triangle.

Original entry on oeis.org

1, 5, 1, 5, 6, 1, 5, 11, 7, 1, 5, 16, 18, 8, 1, 5, 21, 34, 26, 9, 1, 5, 26, 55, 60, 35, 10, 1, 5, 31, 81, 115, 95, 45, 11, 1, 5, 36, 112, 196, 210, 140, 56, 12, 1, 5, 41, 148, 308, 406, 350, 196, 68, 13, 1, 5, 46, 189, 456, 714, 756, 546, 264, 81, 14, 1, 5, 51, 235, 645, 1170
Offset: 0

Views

Author

Wolfdieter Lang, Apr 22 2004

Keywords

Comments

This is the fifth member, d=5, in the family of triangles of figurate numbers, called (d,1) Pascal triangles: A007318 (Pascal), A029653, A093560-1, for d=1..4.
This is an example of a Riordan triangle (see A093560 for a comment and A053121 for a comment and the 1991 Shapiro et al. reference on the Riordan group). 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)=(1+4*z)/(1-(1+x)*z).
The SW-NE diagonals give A022095(n-1) = Sum_{k=0..ceiling((n-1)/2)} a(n-1-k,k), n >= 1, with n=0 value 4. Observation by Paul Barry, Apr 29 2004. Proof via recursion relations and comparison of inputs.
The array F(5;n,m) gives in the columns m >= 1 the figurate numbers based on A016861, including the heptagonal numbers A000566 (see the W. Lang link).
For a closed-form formula for generalized Pascal's triangle see A228576. - Boris Putievskiy, Sep 09 2013
The n-th row polynomial is (4 + x)*(1 + x)^(n-1) for n >= 1. More generally, the n-th row polynomial of the Riordan array ( (1-a*x)/(1-b*x), x/(1-b*x) ) is (b - a + x)*(b + x)^(n-1) for n >= 1. - Peter Bala, Mar 02 2018

Examples

			Triangle begins
  [1];
  [5,  1];
  [5,  6,  1];
  [5, 11,  7,  1];
  ...
		

References

  • Kurt Hawlitschek, Johann Faulhaber 1580-1635, Veroeffentlichung der Stadtbibliothek Ulm, Band 18, Ulm, Germany, 1995, Ch. 2.1.4. Figurierte Zahlen.
  • Ivo Schneider, Johannes Faulhaber 1580-1635, Birkhäuser, Basel, Boston, Berlin, 1993, ch.5, pp. 109-122.

Crossrefs

Cf. Row sums: A007283(n-1), n>=1, 1 for n=0. A082505(n+1), alternating row sums are 1 for n=0, 4 for n=2 and 0 else.
Column sequences give for m=1..9: A016861, A000566 (heptagonal), A002413, A002418, A027800, A051946, A050484, A052255, A055844.

Programs

  • Haskell
    a093562 n k = a093562_tabl !! n !! k
    a093562_row n = a093562_tabl !! n
    a093562_tabl = [1] : iterate
                   (\row -> zipWith (+) ([0] ++ row) (row ++ [0])) [5, 1]
    -- Reinhard Zumkeller, Aug 31 2014
    
  • Python
    from math import comb, isqrt
    def A093562(n): return comb(r:=(m:=isqrt(k:=n+1<<1))-(k<=m*(m+1)),a:=n-comb(r+1,2))*(r+(r-a<<2))//r if n else 1 # Chai Wah Wu, Nov 12 2024

Formula

a(n, m) = F(5;n-m, m) for 0<= m <= n, otherwise 0, with F(5;0, 0)=1, F(5;n, 0)=5 if n>=1 and F(5;n, m):=(5*n+m)*binomial(n+m-1, m-1)/m if m>=1.
G.f. column m (without leading zeros): (1+4*x)/(1-x)^(m+1), m>=0.
Recursion: a(n, m)=0 if m>n, a(0, 0)= 1; a(n, 0)=5 if n>=1; a(n, m)= a(n-1, m) + a(n-1, m-1).
T(n, k) = C(n, k) + 4*C(n-1, k). - Philippe Deléham, Aug 28 2005
exp(x) * e.g.f. for row n = e.g.f. for diagonal n. For example, for n = 3 we have exp(x)*(5 + 11*x + 7*x^2/2! + x^3/3!) = 5 + 16*x + 34*x^2/2! + 60*x^3/3! + 95*x^4/4! + .... The same property holds more generally for Riordan arrays of the form ( f(x), x/(1 - x) ). - Peter Bala, Dec 22 2014

A254142 a(n) = (9*n+10)*binomial(n+9,9)/10.

Original entry on oeis.org

1, 19, 154, 814, 3289, 11011, 32032, 83512, 199342, 442442, 923780, 1830764, 3468374, 6317234, 11113784, 18958808, 31461815, 50930165, 80613390, 125014890, 190285095, 284712285, 419329560, 608658960, 871616460, 1232604516, 1722822024, 2381824984
Offset: 0

Views

Author

Bruno Berselli, Jan 26 2015

Keywords

Comments

Partial sums of A056003.
If n is of the form 8*k+2*(-1)^k-1 or 8*k+2*(-1)^k-2 then a(n) is odd.

Crossrefs

Cf. sequences of the type (k*n+k+1)*binomial(n+k,k)/(k+1): A000217 (k=1), A000330 (k=2), A001296 (k=3), A034263 (k=4), A051946 (k=5), A034265 (k=6), A034266 (k=7), A056122 (k=8), this sequence (k=9).

Programs

  • GAP
    List([0..30], n-> (9*n+10)*Binomial(n+9,9)/10); # G. C. Greubel, Aug 28 2019
  • Magma
    [(9*n+10)*Binomial(n+9,9)/10: n in [0..30]];
    
  • Maple
    seq((9*n+10)*binomial(n+9,9)/10, n=0..30); # G. C. Greubel, Aug 28 2019
  • Mathematica
    Table[(9n+10)Binomial[n+9, 9]/10, {n, 0, 30}]
  • PARI
    vector(30, n, n--; (9*n+10)*binomial(n+9, 9)/10)
    
  • Sage
    [(9*n+10)*binomial(n+9,9)/10 for n in (0..30)]
    

Formula

G.f.: (1 + 8*x)/(1-x)^11.
a(n) = Sum_{i=0..n} (i+1)*A000581(i+8).
a(n+1) = 8*A001287(n+10) + A001287(n+11).

A125234 Triangle T(n,k) read by rows: the k-th column contains the k-fold iterated partial sum of A000566.

Original entry on oeis.org

1, 7, 1, 18, 8, 1, 34, 26, 9, 1, 55, 60, 35, 10, 1, 81, 115, 95, 45, 11, 1, 112, 196, 210, 140, 56, 12, 1, 148, 308, 406, 350, 196, 68, 13, 1, 189, 456, 714, 756, 546, 264, 81, 14, 1, 235, 645, 1170, 1470, 1302, 810, 345, 95, 15, 1, 286, 880, 1815, 2640, 2772, 2112, 1155, 440, 110, 16, 1
Offset: 1

Views

Author

Gary W. Adamson, Nov 24 2006

Keywords

Comments

The leftmost column contains the heptagonal numbers A000566.
The adjacent columns to the right are A002413, A002418, A027800, A051946, A050484.
Row sums = 1, 8, 27, 70, 161, 348, 727, ... = 6*(2^n-1)-5*n.

Examples

			First few rows of the triangle are:
  1;
  7, 1;
  18, 8, 1;
  34, 26, 9, 1;
  55, 60, 35, 10, 1;
  81, 115, 95, 45, 11, 1;
  112, 196, 210, 140, 56, 12, 1;
Example: T(6,2) = 95 = 35 + 60 = T(5,2) + T(5,1).
		

References

  • Albert H. Beiler, Recreations in the Theory of Numbers, Dover, 1966, p. 189.

Crossrefs

Analogous triangles for the hexagonal and pentagonal numbers are A125233 and A125232.

Programs

  • Maple
    A000566 := proc(n) n*(5*n-3)/2 ; end: A125234 := proc(n,k) if k = 0 then A000566(n); elif k>= n then 0 ; else procname(n-1,k-1)+procname(n-1,k) ; fi; end: seq(seq(A125234(n,k),k=0..n-1),n=1..16) ; # R. J. Mathar, Sep 09 2009
  • Mathematica
    A000566[n_] := n(5n-3)/2;
    T[n_, k_] := Which[k == 0, A000566[n], k >= n, 0, True, T[n-1, k-1] + T[n-1, k] ];
    Table[Table[T[n, k], {k, 0, n-1}], {n, 1, 11}] // Flatten (* Jean-François Alcover, Oct 26 2023, after R. J. Mathar *)

Formula

T(n,0) = A000566(n). T(n,k) = T(n-1,k) + T(n-1,k-1), k>0.

Extensions

Edited and extended by R. J. Mathar, Sep 09 2009

A143130 Triangle read by rows, A000012 * (A000332 * 0^(n-k)) * A000012, 0<=k<=n.

Original entry on oeis.org

1, 6, 5, 21, 20, 15, 56, 55, 50, 35, 126, 125, 120, 105, 70, 252, 251, 246, 231, 196, 126, 462, 461, 456, 441, 406, 336, 210, 792, 791, 786, 771, 736, 666, 540, 330, 1287, 1286, 1281, 1266, 1231, 1161, 1035, 825, 495, 2002, 2001, 1996, 1981, 1946, 1876, 1750
Offset: 1

Views

Author

Gary W. Adamson, Jul 27 2008

Keywords

Comments

Row sums = A051946: (1, 11, 56, 196, 546, 1302,...).

Examples

			First few rows of the triangle =
1;
6, 5;
21, 20, 15;
56, 55, 50, 35;
126, 125, 120, 105, 70;
252, 251, 246, 231, 196, 126;
462, 461, 456, 441, 406, 336, 210;
792, 791, 786, 771, 736, 666, 540, 330;
...
		

Crossrefs

Formula

Triangle read by rows, A000012 * (A000332 * 0^(n-k)) * A000012, 0<=k<=n; where A000332 starts (1, 5, 15, 35, 70,...).
Showing 1-5 of 5 results.