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 1-6 of 6 results.

A173188 a(n) = binomial(n + 5, 5)*9^n.

Original entry on oeis.org

1, 54, 1701, 40824, 826686, 14880348, 245525742, 3788111448, 55401129927, 775615818978, 10470813556203, 137072468372112, 1747673971744428, 21778706417122872, 266011342666286508, 3192136111995438096, 37707107822946112509, 439176902879019428046
Offset: 0

Views

Author

Zerinvary Lajos, Feb 12 2010

Keywords

Comments

Number of n-permutations (n>=5) of 10 objects p, r, q, u, v, w, z, x, y, z with repetition allowed, containing exactly five (5) u's.

Crossrefs

Programs

  • Magma
    [Binomial(n+5, 5)*9^n: n in [0..20]]; // Vincenzo Librandi, Oct 13 2011
  • Mathematica
    Table[Binomial[n + 5, 5]*9^n, {n, 0, 20}]

Formula

a(n) = C(n + 5, 5)*9^n.
From Amiram Eldar, Aug 28 2022: (Start)
Sum_{n>=0} 1/a(n) = 184320*log(9/8) - 86835/4.
Sum_{n>=0} (-1)^n/a(n) = 450000*log(10/9) - 189645/4. (End)

A173191 a(n) = binomial(n + 6, 6)*9^n.

Original entry on oeis.org

1, 63, 2268, 61236, 1377810, 27280638, 491051484, 8207574804, 129269303163, 1939039547445, 27922169483208, 388371993720984, 5243021915233284, 68965903654222428, 886704475554288360, 11172476391984033336, 138259395350802412533, 1683511461036241140843
Offset: 0

Views

Author

Zerinvary Lajos, Feb 12 2010

Keywords

Comments

Number of n-permutations (n>=6) of 10 objects p, r, q, u, v, w, z, x, y, z with repetition allowed, containing exactly six (6) u's.

Crossrefs

Programs

Formula

a(n) = C(n + 6, 6)*9^n.
From Amiram Eldar, Aug 29 2022: (Start)
Sum_{n>=0} 1/a(n) = 1042074/5 - 1769472*log(9/8).
Sum_{n>=0} (-1)^n/a(n) = 5400000*log(10/9) - 2844729/5. (End)

A173192 a(n) = binomial(n + 7, 7)*9^n.

Original entry on oeis.org

1, 72, 2916, 87480, 2165130, 46766808, 911952756, 16415149608, 277005649635, 4432090394160, 67810983030648, 998670840996816, 14231059484204628, 197045439012064080, 2660113426662865080, 35113497231949819056, 454280870438350784037, 5772039294981398197176
Offset: 0

Views

Author

Zerinvary Lajos, Feb 12 2010

Keywords

Comments

Number of n-permutations (n>=7) of 10 objects p, r, q, u, v, w, z, x, y, z with repetition allowed, containing exactly 7 u's.

Crossrefs

Programs

Formula

a(n) = C(n + 7, 7)*9^n.
From Amiram Eldar, Aug 29 2022: (Start)
Sum_{n>=0} 1/a(n) = 16515072*log(9/8) - 19451943/10.
Sum_{n>=0} (-1)^n/a(n) = 63000000*log(10/9) - 13275423/2. (End)

A317052 Triangle read by rows: T(0,0) = 1; T(n,k) = 9*T(n-1,k) + T(n-2,k-1) for k = 0..floor(n/2); T(n,k)=0 for n or k < 0.

Original entry on oeis.org

1, 9, 81, 1, 729, 18, 6561, 243, 1, 59049, 2916, 27, 531441, 32805, 486, 1, 4782969, 354294, 7290, 36, 43046721, 3720087, 98415, 810, 1, 387420489, 38263752, 1240029, 14580, 45, 3486784401, 387420489, 14880348, 229635, 1215, 1, 31381059609, 3874204890, 172186884, 3306744, 25515, 54
Offset: 0

Views

Author

Zagros Lalo, Jul 20 2018

Keywords

Comments

The numbers in rows of the triangle are along skew diagonals pointing top-left in center-justified triangle given in A013616 ((1+9*x)^n) and along skew diagonals pointing top-right in center-justified triangle given in A038291 ((9+x)^n).
The coefficients in the expansion of 1/(1-9*x-x^2) are given by the sequence generated by the row sums (see A099371).
If s(n) is the row sum at n, then the ratio s(n)/s(n-1) is approximately 9.109772228646443655... (a metallic mean), when n approaches infinity; (see A176522: ((9+sqrt(85))/2)).

Examples

			Triangle begins:
  1;
  9;
  81, 1;
  729, 18;
  6561, 243, 1;
  59049, 2916, 27;
  531441, 32805, 486, 1;
  4782969, 354294, 7290, 36;
  43046721, 3720087, 98415, 810, 1;
  387420489, 38263752, 1240029, 14580, 45;
  3486784401, 387420489, 14880348, 229635, 1215, 1;
  31381059609, 3874204890, 172186884, 3306744, 25515, 54;
		

References

  • Shara Lalo and Zagros Lalo, Polynomial Expansion Theorems and Number Triangles, Zana Publishing, 2018, ISBN: 978-1-9995914-0-3, pp. 70, 100.

Crossrefs

Row sums give A099371.
Cf. A001019 (column 0), A053540 (column 1), A081139 (column 2), A173187 (column 3), A173000 (column 4).

Programs

  • Mathematica
    t[0, 0] = 1; t[n_, k_] := If[n < 0 || k < 0, 0, 9 t[n - 1, k] + t[n - 2, k - 1]]; Table[t[n, k], {n, 0, 11}, {k, 0, Floor[n/2]}] // Flatten
  • PARI
    T(n, k) = if ((n<0) || (k<0), 0, if ((n==0) && (k==0), 1, 9*T(n-1, k)+T(n-2, k-1)));
    tabf(nn) = for (n=0, nn, for (k=0, n\2, print1(T(n, k), ", ")); print); \\ Michel Marcus, Jul 20 2018

A196221 Binomial(n+10, 10)*9^n.

Original entry on oeis.org

1, 99, 5346, 208494, 6567561, 177324147, 4255779528, 93019181112, 1883638417518, 35789129932842, 644204338791156, 11068601821048044, 182631930047292726, 2908062270753045714, 44867246463046991016, 673008696945704865240, 9842752192830933654135, 140693457815171581056165, 1969708409412402134786310
Offset: 0

Views

Author

Vincenzo Librandi, Oct 13 2011

Keywords

Crossrefs

Programs

  • Magma
    [Binomial(n+10, 10)*9^n: n in [0..20]];

Formula

a(n) = C(n+10, 10)*9^n.
G.f. -1 / (9*x-1)^11 . - R. J. Mathar, Oct 13 2011

A197194 a(n) = binomial(n+9, 9)*9^n.

Original entry on oeis.org

1, 90, 4455, 160380, 4691115, 118216098, 2659862205, 54717165360, 1046465787510, 18836384175180, 322102169395578, 5270762771927640, 83014513657860330, 1264374900327411180, 18694686026269579590, 269203478778281946096, 3785673920319589866975, 52108688079693178168950, 703467289075857905280825
Offset: 0

Views

Author

Vincenzo Librandi, Oct 13 2011

Keywords

Crossrefs

Programs

  • Magma
    [Binomial(n+9, 9)*9^n: n in [0..20]];
    
  • Mathematica
    Table[Binomial[n+9,9]9^n,{n,0,20}] (* Harvey P. Dale, Feb 22 2020 *)
  • Python
    A197194_list, m, k = [], [1]*10, 1
    for _ in range(10**2):
        A197194_list.append(k*m[-1])
        k *= 9
        for i in range(9):
            m[i+1] += m[i] # Chai Wah Wu, Jan 24 2016

Formula

a(n) = C(n + 9, 9)*9^n.
G.f.: 1 / (9*x-1)^10 . - R. J. Mathar, Oct 13 2011
From Amiram Eldar, Apr 17 2022: (Start)
Sum_{n>=0} 1/a(n) = 1358954496*log(9/8) - 44817299757/280.
Sum_{n>=0} (-1)^n/a(n) = 8100000000*log(10/9) - 47791529847/56. (End)
Showing 1-6 of 6 results.