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.

A093564 (7,1) Pascal triangle.

Original entry on oeis.org

1, 7, 1, 7, 8, 1, 7, 15, 9, 1, 7, 22, 24, 10, 1, 7, 29, 46, 34, 11, 1, 7, 36, 75, 80, 45, 12, 1, 7, 43, 111, 155, 125, 57, 13, 1, 7, 50, 154, 266, 280, 182, 70, 14, 1, 7, 57, 204, 420, 546, 462, 252, 84, 15, 1, 7, 64, 261, 624, 966, 1008, 714, 336, 99, 16, 1, 7, 71, 325, 885
Offset: 0

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Author

Wolfdieter Lang, Apr 22 2004

Keywords

Comments

The array F(7;n,m) gives in the columns m>=1 the figurate numbers based on A016993, including the 9-gonal numbers A001106, (see the W. Lang link).
This is the seventh member, d=7, in the family of triangles of figurate numbers, called (d,1) Pascal triangles: A007318 (Pascal), A029653, A093560-3, for d=1..6.
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+6*z)/(1-(1+x)*z).
The SW-NE diagonals give A022097(n-1) = Sum_{k=0..ceiling((n-1)/2)} a(n-1-k,k), n >= 1, with n=0 value 6. Observation by Paul Barry, Apr 29 2004. Proof via recursion relations and comparison of inputs.

Examples

			Triangle begins
  [1];
  [7,  1];
  [7,  8,  1];
  [7, 15,  9,  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

Row sums: A000079(n+2), n>=1, 1 for n=0, alternating row sums are 1 for n=0, 6 for n=2 and 0 otherwise.
The column sequences give for m=1..9: A016993, A001106 (9-gonal), A007584, A051740, A051877, A050403, A027818, A034266, A055994.
Cf. A093565 (d=8).

Programs

  • Haskell
    a093564 n k = a093564_tabl !! n !! k
    a093564_row n = a093564_tabl !! n
    a093564_tabl = [1] : iterate
                   (\row -> zipWith (+) ([0] ++ row) (row ++ [0])) [7, 1]
    -- Reinhard Zumkeller, Sep 01 2014
  • Maple
    N:= 20: # to get the first N rows
    T:=Matrix(N,N):
    T[1,1]:= 1:
    for m from 2 to N do
    T[m,1]:= 7:
    T[m,2..m]:= T[m-1,1..m-1] + T[m-1,2..m];
    od:
    for m from 1 to N do
    convert(T[m,1..m],list)
    od; # Robert Israel, Dec 28 2014

Formula

a(n, m)=F(7;n-m, m) for 0<= m <= n, otherwise 0, with F(7;0, 0)=1, F(7;n, 0)=7 if n>=1 and F(7;n, m):=(7*n+m)*binomial(n+m-1, m-1)/m if m>=1.
Recursion: a(n, m)=0 if m>n, a(0, 0)= 1; a(n, 0)=7 if n>=1; a(n, m)= a(n-1, m) + a(n-1, m-1).
G.f. column m (without leading zeros): (1+6*x)/(1-x)^(m+1), m>=0.
T(n, k) = C(n, k) + 6*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)*(7 + 15*x + 9*x^2/2! + x^3/3!) = 7 + 22*x + 46*x^2/2! + 80*x^3/3! + 125*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).

A055994 Expansion of (1+6x)/(1-x)^10.

Original entry on oeis.org

1, 16, 115, 550, 2035, 6292, 17017, 41470, 92950, 194480, 384098, 722228, 1301690, 2261000, 3801710, 6210644, 9887999, 15382400, 23434125, 35027850, 51456405, 74397180, 106002975, 149009250, 206859900, 283853856, 385314996, 517788040
Offset: 0

Views

Author

Barry E. Williams, Jun 04 2000

Keywords

Comments

Partial sums of A034266. - Vladimir Joseph Stephan Orlovsky, Jun 25 2009

References

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

Crossrefs

Cf. A034266.
Cf. A093564 ((7, 1) Pascal, column m=9). Partial sums of A034266.

Programs

  • Magma
    [((7*n+9)*Binomial(n+8,8))/9: n in [0..40]]; // Vincenzo Librandi, Jul 30 2014
  • Mathematica
    CoefficientList[Series[(1 + 6 x)/(1 - x)^10, {x, 0, 50}], x] (* Vincenzo Librandi, Jul 30 2014 *)
    LinearRecurrence[{10,-45,120,-210,252,-210,120,-45,10,-1},{1,16,115,550,2035,6292,17017,41470,92950,194480},30] (* Harvey P. Dale, Sep 07 2022 *)

Formula

a(n) = (7n+9)*C(n+8, 8)/9.
G.f.: (1+6x)/(1-x)^10.
Showing 1-3 of 3 results.