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 31-36 of 36 results.

A147716 Triangle of coefficients in expansion of (14 + x)^n.

Original entry on oeis.org

1, 14, 1, 196, 28, 1, 2744, 588, 42, 1, 38416, 10976, 1176, 56, 1, 537824, 192080, 27440, 1960, 70, 1, 7529536, 3226944, 576240, 54880, 2940, 84, 1, 105413504, 52706752, 11294304, 1344560, 96040, 4116, 98, 1, 1475789056, 843308032, 210827008, 30118144, 2689120, 153664, 5488, 112, 1
Offset: 0

Views

Author

Philippe Deléham, Nov 11 2008

Keywords

Comments

Triangle T(n,k), read by rows, given by [14, 0, 0, 0, 0, 0, 0, ...] DELTA [1, 0, 0, 0, 0, 0, 0, ...] where DELTA is the operator defined in A084938.

Examples

			Triangle begins :
       1;
      14,      1;
     196,     28,     1;
    2744,    588,    42,    1;
   38416,  10976,  1176,   56,  1;
  537824, 192080, 27440, 1960, 70, 1;
		

Crossrefs

Sequences of the form q^(n-k)*binomial(n, k): A007318 (q=1), A038207 (q=2), A027465 (q=3), A038231 (q=4), A038243 (q=5), A038255 (q=6), A027466 (q=7), A038279 (q=8), A038291 (q=9), A038303 (q=10), A038315 (q=11), A038327 (q=12), A133371 (q=13), this sequence (q=14), A027467 (q=15).

Programs

  • Magma
    [14^(n-k)*Binomial(n,k): k in [0..n], n in [0..12]]; // G. C. Greubel, May 15 2021
    
  • Mathematica
    With[{m=8}, CoefficientList[CoefficientList[Series[1/(1-14*x-x*y), {x, 0, m}, {y, 0, m}], x], y]]//Flatten (* Georg Fischer, Feb 17 2020 *)
  • Sage
    flatten([[14^(n-k)*binomial(n,k) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, May 15 2021

Formula

T(n,k) = binomial(n,k) * 14^(n-k).
G.f.: 1/(1 - 14*x - x*y). - R. J. Mathar, Aug 12 2015
Sum_{k=0..n} T(n, k) = 15^n = A001024(n). - G. C. Greubel, May 15 2021

Extensions

a(36) corrected by Georg Fischer, Feb 17 2020

A164942 Triangle, read by rows, T(n,k) = (-1)^k*binomial(n, k)*3^(n-k).

Original entry on oeis.org

1, 3, -1, 9, -6, 1, 27, -27, 9, -1, 81, -108, 54, -12, 1, 243, -405, 270, -90, 15, -1, 729, -1458, 1215, -540, 135, -18, 1, 2187, -5103, 5103, -2835, 945, -189, 21, -1, 6561, -17496, 20412, -13608, 5670, -1512, 252, -24, 1, 19683, -59049, 78732, -61236, 30618, -10206, 2268, -324, 27, -1
Offset: 0

Views

Author

Mark Dols, Sep 01 2009

Keywords

Comments

Rows sum up to A000079, antidiagonals sum up to A001906.
Triangle, read by rows, given by [3,0,0,0,0,0,0,0,...] DELTA [ -1,0,0,0,0,0,0,0,...] where DELTA is the operator defined in A084938. - Philippe Deléham, Sep 02 2009
Row n: expansion of (3-x)^n. - Philippe Deléham, Oct 09 2011
Essentially the same as the inverse of A027465, but with opposite signs in every other row. - M. F. Hasler, Feb 17 2020
The inverse of A027465 is (-1)^(n-k)*binomial(n, k)*3^(n - k). - G. C. Greubel, Feb 17 2020

Examples

			Begins as triangle:
    1;
    3,   -1;
    9,   -6,    1;
   27,  -27,    9,   -1;
   81, -108,   54,  -12,    1;
  243, -405,  270,  -90,   15,   -1;
		

Crossrefs

Programs

  • Magma
    [(-1)^k*Binomial(n, k)*3^(n-k): k in [0..n], n in [0..10]]; // G. C. Greubel, Feb 17 2020
    
  • Maple
    seq(seq( (-1)^k*binomial(n, k)*3^(n-k), k=0..n), n=0..10); # G. C. Greubel, Feb 17 2020
  • Mathematica
    With[{m = 9}, CoefficientList[CoefficientList[Series[1/(1-3*x+x*y), {x, 0, m}, {y, 0, m}], x], y]] // Flatten (* Georg Fischer, Feb 17 2020 *)
  • Sage
    [[(-1)^k*binomial(n, k)*3^(n-k) for k in (0..n)] for n in (0..10)] # G. C. Greubel, Feb 17 2020

Formula

T(n,k) = (-1)^n*(Inverse of A027465).
T(n,k) = 3*T(n-1,k) - T(n-1,k-1). - Philippe Deléham, Oct 09 2011
G.f.: 1/(1-3*x+x*y). - R. J. Mathar, Aug 11 2015

Extensions

More terms from Philippe Deléham, Oct 09 2011
a(46) corrected by Georg Fischer, Feb 17 2020
Title changed by G. C. Greubel, Feb 17 2020

A318772 Triangle read by rows: T(0,0) = 1; T(n,k) = T(n-1,k) + 3 * T(n-4,k-1) for k = 0..floor(n/4); T(n,k)=0 for n or k < 0.

Original entry on oeis.org

1, 1, 1, 1, 1, 3, 1, 6, 1, 9, 1, 12, 1, 15, 9, 1, 18, 27, 1, 21, 54, 1, 24, 90, 1, 27, 135, 27, 1, 30, 189, 108, 1, 33, 252, 270, 1, 36, 324, 540, 1, 39, 405, 945, 81, 1, 42, 495, 1512, 405, 1, 45, 594, 2268, 1215, 1, 48, 702, 3240, 2835, 1, 51, 819, 4455, 5670, 243, 1, 54, 945, 5940, 10206, 1458
Offset: 0

Views

Author

Zagros Lalo, Sep 04 2018

Keywords

Comments

The numbers in rows of the triangle are along a "third layer" skew diagonals pointing top-right in center-justified triangle given in A013610 ((1+3*x)^n) and along a "third layer" skew diagonals pointing top-left in center-justified triangle given in A027465 ((3+x)^n), see links. (Note: First layer of skew diagonals in center-justified triangles of coefficients in expansions of (1+3*x)^n and (3+x)^n are given in A304236 and A304249 respectively.)
The coefficients in the expansion of 1/(1-x-3*x^4) are given by the sequence generated by the row sums.
If s(n) is the row sum at n, then the ratio s(n)/s(n-1) is approximately 1.6580980673722..., when n approaches infinity.

Examples

			Triangle begins:
  1;
  1;
  1;
  1;
  1,  3;
  1,  6;
  1,  9;
  1, 12;
  1, 15,   9;
  1, 18,  27;
  1, 21,  54;
  1, 24,  90;
  1, 27, 135,   27;
  1, 30, 189,  108;
  1, 33, 252,  270;
  1, 36, 324,  540;
  1, 39, 405,  945,   81;
  1, 42, 495, 1512,  405;
  1, 45, 594, 2268, 1215;
  ...
		

References

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

Crossrefs

Row sums give A318774.

Programs

  • Magma
    [3^k*Binomial(n-3*k,k): k in [0..Floor(n/4)], n in [0..24]]; // G. C. Greubel, May 12 2021
    
  • Mathematica
    T[n_, k_]:= T[n, k]= 3^k(n-3k)!/((n-4k)! k!); Table[T[n, k], {n, 0, 21}, {k, 0, Floor[n/4]} ] // Flatten
    T[0, 0] = 1; T[n_, k_] := T[n, k] = If[n<0 || k<0, 0, T[n-1, k] + 3T[n-4, k-1]]; Table[T[n, k], {n, 0, 21}, {k, 0, Floor[n/4]}] // Flatten
  • Sage
    flatten([[3^k*binomial(n-3*k,k) for k in (0..n//4)] for n in (0..24)]) # G. C. Greubel, May 12 2021

Formula

T(n,k) = 3^k * (n - 3*k)!/ ((n - 4*k)! k!), where n >= 0 and 0 <= k <= floor(n/4).

A318773 Triangle T(n,k) = 3*T(n-1,k) + T(n-4,k-1) for k = 0..floor(n/4), with T(0,0) = 1 and T(n,k) = 0 for n or k < 0, read by rows.

Original entry on oeis.org

1, 3, 9, 27, 81, 1, 243, 6, 729, 27, 2187, 108, 6561, 405, 1, 19683, 1458, 9, 59049, 5103, 54, 177147, 17496, 270, 531441, 59049, 1215, 1, 1594323, 196830, 5103, 12, 4782969, 649539, 20412, 90, 14348907, 2125764, 78732, 540, 43046721, 6908733, 295245, 2835, 1, 129140163, 22320522, 1082565, 13608, 15
Offset: 0

Views

Author

Zagros Lalo, Sep 04 2018

Keywords

Comments

The numbers in rows of the triangle are along a "third layer" skew diagonals pointing top-left in center-justified triangle given in A013610 ((1+3*x)^n) and along a "third layer" skew diagonals pointing top-right in center-justified triangle given in A027465 ((3+x)^n), see links. (Note: First layer of skew diagonals in center-justified triangles of coefficients in expansions of (1+3*x)^n and (3+x)^n are given in A304236 and A304249 respectively.)
The coefficients in the expansion of 1/(1-3*x-x^4) are given by the sequence generated by the row sums.
If s(n) is the row sum at n, then the ratio s(n)/s(n-1) is approximately 3.035744112294..., when n approaches infinity.

Examples

			Triangle begins:
          1;
          3;
          9;
         27;
         81,        1;
        243,        6;
        729,       27;
       2187,      108;
       6561,      405,       1;
      19683,     1458,       9;
      59049,     5103,      54;
     177147,    17496,     270;
     531441,    59049,    1215,     1;
    1594323,   196830,    5103,    12;
    4782969,   649539,   20412,    90;
   14348907,  2125764,   78732,   540;
   43046721,  6908733,  295245,  2835,   1;
  129140163, 22320522, 1082565, 13608,  15;
  387420489, 71744535, 3897234, 61236, 135;
  ...
		

References

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

Crossrefs

Row sums give A052917.
Cf. A000244 (column 0), A027471 (column 1), A027472 (column 2), A036216 (column 3).
Sequences of the form 3^(n-q*k)*binomial(n-(q-1)*k, k): A027465 (q=1), A304249 (q=2), A317497 (q=3), this sequence (q=4).

Programs

  • Magma
    [3^(n-4*k)*Binomial(n-3*k,k): k in [0..Floor(n/4)], n in [0..24]]; // G. C. Greubel, May 12 2021
    
  • Mathematica
    T[n_, k_]:= T[n, k] = 3^(n-4k)*(n-3k)!/((n-4k)! k!); Table[T[n, k], {n, 0, 17}, {k, 0, Floor[n/4]} ]//Flatten
    T[0, 0] = 1; T[n_, k_]:= T[n, k] = If[n<0 || k<0, 0, 3T[n-1, k] + T[n-4, k-1]]; Table[T[n, k], {n, 0, 17}, {k, 0, Floor[n/4]}]//Flatten
  • Sage
    flatten([[3^(n-4*k)*binomial(n-3*k,k) for k in (0..n//4)] for n in (0..24)]) # G. C. Greubel, May 12 2021

Formula

T(n,k) = 3^(n-4*k) * (n-3*k)!/(k! * (n-4*k)!) where n >= 0 and 0 <= k <= floor(n/4).

A113335 a(n) = 3^5 * binomial(n+4, 5).

Original entry on oeis.org

243, 1458, 5103, 13608, 30618, 61236, 112266, 192456, 312741, 486486, 729729, 1061424, 1503684, 2082024, 2825604, 3767472, 4944807, 6399162, 8176707, 10328472, 12910590, 15984540, 19617390, 23882040, 28857465, 34628958, 41288373, 48934368, 57672648, 67616208
Offset: 1

Views

Author

Zerinvary Lajos, Aug 06 2008

Keywords

Crossrefs

Cf. A027465.
Sequences of the form 3^m*binomial(n+m-1, m): A008585 (m=1), A027468 (m=2), A134171 (m=3), A102741 (m=4), this sequence (m=5).

Programs

  • Magma
    [3^5*Binomial(n+4,5): n in [1..30]]; // G. C. Greubel, May 17 2021
    
  • Maple
    seq(binomial(n+4,5)*3^5, n=1..27);
  • Mathematica
    With[{c=3^5},Table[c Binomial[n+4,5],{n,30}]]  (* Harvey P. Dale, Apr 11 2011 *)
  • Sage
    [3^5*binomial(n+4,5) for n in (1..30)] # G. C. Greubel, May 17 2021

Formula

a(n) = 3^5 * binomial(n+4, 5), n >= 1.
From G. C. Greubel, May 17 2021: (Start)
G.f.: 243*x/(1-x)^6.
E.g.f.: (81/40)*x*(120 + 240*x + 120*x^2 + 20*x^3 + x^4)*exp(x). (End)
From Amiram Eldar, Aug 29 2022: (Start)
Sum_{n>=1} 1/a(n) = 5/972.
Sum_{n>=1} (-1)^(n+1)/a(n) = 80*log(2)/243 - 655/2916. (End)

A318774 Coefficients in expansion of 1/(1 - x - 3*x^4).

Original entry on oeis.org

1, 1, 1, 1, 4, 7, 10, 13, 25, 46, 76, 115, 190, 328, 556, 901, 1471, 2455, 4123, 6826, 11239, 18604, 30973, 51451, 85168, 140980, 233899, 388252, 643756, 1066696, 1768393, 2933149, 4864417, 8064505, 13369684, 22169131, 36762382, 60955897, 101064949, 167572342, 277859488, 460727179, 763922026, 1266639052
Offset: 0

Views

Author

Zagros Lalo, Sep 04 2018

Keywords

Comments

The coefficients in the expansion of 1/(1 - x - 3*x^4) are given by the sequence generated by the row sums in triangle A318772.
Coefficients in expansion of 1/(1 - x - 3*x^4) are given by the sum of numbers along "third Layer" skew diagonals pointing top-right in triangle A013610 ((1+3x)^n) and by the sum of numbers along "third Layer" skew diagonals pointing top-left in triangle A027465 ((3+x)^n), see links.

References

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

Crossrefs

Essentially a duplicate of A143454.

Programs

  • Magma
    [n le 4 select 1 else Self(n-1) +3*Self(n-4): n in [1..51]]; // G. C. Greubel, May 08 2021
    
  • Mathematica
    CoefficientList[Series[1/(1-x-3x^4), {x, 0, 50}], x]
    a[n_]:= a[n]= If[n<4, 1, a[n-1] + 3*a[n-4]]; Table[a[n], {n,0,50}]
    LinearRecurrence[{1,0,0,3}, {1,1,1,1}, 51]
  • PARI
    my(p=Mod('x,x^4-'x^3-3)); a(n) = vecsum(Vec(lift(p^n))); \\ Kevin Ryde, May 11 2021
  • Sage
    def a(n): return 1 if (n<4) else a(n-1) + 3*a(n-4)
    [a(n) for n in (0..50)] # G. C. Greubel, May 08 2021
    

Formula

a(n) = a(n-1) + 3*a(n-4) for n >= 0, a(n)=0 for n < 0, with a(0) = a(1) = a(2) = a(3) = 1.
Previous Showing 31-36 of 36 results.