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.

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A090394 Ninth diagonal (m=8) of triangle A084938; a(n) = A084938(n+8,n) = (n^8 + 84*n^7 + 3346*n^6 + 84840*n^5 + 1550689*n^4 + 21632436*n^3 + 224782284*n^2 + 1377648720*n)/40320.

Original entry on oeis.org

0, 40320, 95616, 170856, 272584, 409360, 592296, 835702, 1157857, 1581921, 2137005, 2859417, 3794103, 4996303, 6533443, 8487285, 10956358, 14058694, 17934894, 22751550, 28705050, 36025794, 44982850, 55889080, 69106767
Offset: 0

Views

Author

Philippe Deléham, Jan 31 2004

Keywords

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{9,-36,84,-126,126,-84,36,-9,1},{0,40320,95616,170856,272584,409360,592296,835702,1157857},30] (* Harvey P. Dale, Apr 04 2017 *)
  • Python
    from itertools import islice
    def A090394_generator():
        m = [1, 7, 33, 135, 531, 2109, 8411, 29093, 0]
        yield m[-1]
        while True:
            for i in range(8):
                m[i+1]+= m[i]
            yield m[-1]
    list(islice(A090394_generator(),0,50,1)) # Chai Wah Wu, Nov 14 2014

Formula

a(n) = A084938(n+8, n) = Sum_{k=0..8} A090238(8, k)*binomial(n, k).
From Chai Wah Wu, Jun 04 2016: (Start)
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) for n > 8.
G.f.: x*(29093*x^7 - 212062*x^6 + 663528*x^5 - 1155496*x^4 + 1209824*x^3 - 761832*x^2 + 267264*x - 40320)/(x - 1)^9. (End)

A092286 Fourth diagonal (m=3) of triangle A084938; a(n) = A084938(n+3,n) = (n^3 + 9*n^2 + 26*n)/6.

Original entry on oeis.org

0, 6, 16, 31, 52, 80, 116, 161, 216, 282, 360, 451, 556, 676, 812, 965, 1136, 1326, 1536, 1767, 2020, 2296, 2596, 2921, 3272, 3650, 4056, 4491, 4956, 5452, 5980, 6541, 7136, 7766, 8432, 9135, 9876, 10656, 11476, 12337, 13240, 14186, 15176
Offset: 0

Views

Author

Philippe Deléham, Jan 30 2004

Keywords

Comments

If X is an n-set and Y a fixed (n-4)-subset of X then a(n-4) is equal to the number of 3-subsets of X intersecting Y. - Milan Janjic, Aug 15 2007
For n>=0, A092286(n) is the number of 2 X 2 matrices with all terms in {0,1,...,n} and (sum of terms) = n + 1. A092286(n) is also the number of 2 X 2 matrices with all terms in {0,1,...,n} and (sum of terms) = 3n - 1. - Clark Kimberling, Mar 20 2012

Crossrefs

Programs

  • Maple
    a:=n->(n^3 + 9*n^2 + 26*n)/6: seq(a(n), n=3..45);
  • Mathematica
    q=60;(Transpose[NestList[Accumulate,Range[q],q]]-Range[q])[[4]] (* Vladimir Joseph Stephan Orlovsky, Apr 08 2011 *)
    Table[(n^3 + 9*n^2 + 26*n)/6, {n, 0, 100}] (* T. D. Noe, Apr 12 2011 *)

Formula

a(n) = A084938(n+3, n) = sum_{k=0..3} A090238(3, k)*binomial(n, k).
From Gary Detlefs, Aug 02 2010: (Start)
a(n) = 1/2 * sum_{k=1..n} (k+3)(k+2).
a(n) = 1/6 * n *(n^2 + 9n + 26). (End)
G.f.: x*(6 - 8*x + 3*x^2)/(1-x)^4. - Colin Barker, Mar 18 2012
Previous Showing 11-12 of 12 results.