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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A253943 a(n) = 3*binomial(n+1,6).

Original entry on oeis.org

3, 21, 84, 252, 630, 1386, 2772, 5148, 9009, 15015, 24024, 37128, 55692, 81396, 116280, 162792, 223839, 302841, 403788, 531300, 690690, 888030, 1130220, 1425060, 1781325, 2208843, 2718576, 3322704, 4034712, 4869480, 5843376, 6974352, 8282043, 9787869, 11515140
Offset: 5

Views

Author

Serhat Bulut, Jan 20 2015

Keywords

Comments

For a set of integers {1,2,...,n}, a(n) is the sum of the 2 smallest elements of each subset with 5 elements, which is 3*C(n+1,6) (for n>=5), hence a(n) = 3*C(n+1,6) = 3*A000579(n+1). - Serhat Bulut, Oktay Erkan Temizkan, Jan 20 2015

Examples

			For A={1,2,3,4,5,6} subsets with 5 elements are {1,2,3,4,5}, {1,2,3,4,6}, {1,2,3,5,6}, {1,2,4,5,6}, {1,3,4,5,6}, {2,3,4,5,6}.
Sum of 2 smallest elements of each subset:
a(6) = (1+2) + (1+2) + (1+2) + (1+2) + (1+3) + (2+3) = 21 = 3*C(6+1,6) = 3*A000579(6+1).
		

Crossrefs

Cf. A000579.

Programs

Formula

a(n) = 3*C(n+1,6) = 3*A000579(n+1).
From Amiram Eldar, Jan 09 2022: (Start)
Sum_{n>=5} 1/a(n) = 2/5.
Sum_{n>=5} (-1)^(n+1)/a(n) = 64*log(2) - 661/15. (End)
From G. C. Greubel, Apr 03 2025: (Start)
G.f.: 3*x^5/(1-x)^7.
E.g.f.: (3/6!)*x^5*(x+6)*exp(x). (End)

Extensions

More terms from Vincenzo Librandi, Feb 13 2015

A289410 Irregular triangular array T(m,k) with m (row) >= 1 and k (column) >= 1 read by rows: number of m-digit numbers whose digit sum is k.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 9, 8, 7, 6, 5, 4, 3, 2, 1, 1, 3, 6, 10, 15, 21, 28, 36, 45, 54, 61, 66, 69, 70, 69, 66, 61, 54, 45, 36, 28, 21, 15, 10, 6, 3, 1, 1, 4, 10, 20, 35, 56, 84, 120, 165, 219, 279, 342, 405, 465, 519, 564, 597, 615, 615, 597, 564, 519, 465, 405, 342, 279, 219, 165, 120, 84
Offset: 1

Views

Author

Miquel Cerda, Jul 05 2017

Keywords

Comments

The m-th row is palindromic; T(m,k) = T(m,9*m+1-k).

Examples

			The irregular triangle T(m,k) begins:
m\k  1  2  3  4  5   6   7   8   9   10   11  12   13   14  15  16  17  18  19
1    1  1  1  1  1   1   1   1   1;
2    1  2  3  4  5   6   7   8   9    9    8   7    6    5   4   3   2   1;
3    1  3  6  10 15  21  28  36  45   54   61  66   69   70  69  66  61  54 45,...;
4    1  4  10 20 35  56  84  120 165  219  279 342  405  465,...;
5    1  5  15 35 70  126 210 330 495  714  992 1330 1725,...;
6    1  6  21 56 126 252 462 792 1287 2001 2992,...;
etc.
Row m(2), column k(4) there are 4 numbers of 2-digits whose digits sum = 4: 13, 22, 31, 40.
		

Crossrefs

The row sums = 9*10^(m-1) = A052268(n). The row lengths = 9*m = A008591(n). The middle diagonal = A071976. (row m=3) = A071817, (row m=4) = A090579, (row m=5) = A090580, (row m=6) = A090581, (row m=7) = A278969, (row m=8) = A278971, (row m=9) = A289354, (column k=3) = A000217, (column k=4) = A000292, (column k=5) = A000332, (column k=6) = A000389, (column k=7) = A000579, (column k=8) = A000580, (column k=9) = A000581, (column k=10) = A035927.

Programs

  • Maple
    row:= proc(m) local g; g:= normal((1 - x^10)^(m-1)*(x - x^10)/(1 - x)^m);
    seq(coeff(g,x,j),j=1..9*m) end proc:
    seq(row(k),k=1..5); # Robert Israel, Jul 19 2017

Formula

G.f. of row m: (1 - x^10)^(m-1)*(x - x^10)/(1 - x)^m.
G.f. as array: (1+x+x^2)*(1+x^3+x^6)*x*y/(1-y*(1+x+x^2+x^3+x^4+x^5+x^6+x^7+x^8+x^9)). - Robert Israel, Jul 19 2017

Extensions

Edited by Robert Israel, Jul 19 2017

A293616 Array of generalized Eulerian number triangles read by ascending antidiagonals, with m >= 0, n >= 0 and 0 <= k <= n.

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 3, 0, 0, 1, 6, 0, 1, 0, 1, 10, 0, 7, 1, 0, 1, 15, 0, 25, 4, 0, 0, 1, 21, 0, 65, 10, 0, 1, 0, 1, 28, 0, 140, 20, 0, 15, 4, 0, 1, 36, 0, 266, 35, 0, 90, 30, 1, 0, 1, 45, 0, 462, 56, 0, 350, 120, 5, 0, 0, 1, 55, 0, 750, 84, 0, 1050, 350, 15, 0, 1, 0
Offset: 0

Views

Author

Peter Luschny, Oct 14 2017

Keywords

Examples

			Array starts:
m\j| 0   1  2     3    4  5       6       7    8  9      10      11      12
---|----------------------------------------------------------------------------
m=0| 1,  0, 0,    0,   0, 0,      0,      0,   0, 0,      0,      0,      0, ...
m=1| 1,  1, 0,    1,   1, 0,      1,      4,   1, 0,      1,     11,     11, ...
m=2| 1,  3, 0,    7,   4, 0,     15,     30,   5, 0,     31,    146,     91, ...
m=3| 1,  6, 0,   25,  10, 0,     90,    120,  15, 0,    301,    896,    406, ...
m=4| 1, 10, 0,   65,  20, 0,    350,    350,  35, 0,   1701,   3696,   1316, ...
m=5| 1, 15, 0,  140,  35, 0,   1050,    840,  70, 0,   6951,  11886,   3486, ...
m=6| 1, 21, 0,  266,  56, 0,   2646,   1764, 126, 0,  22827,  32172,   8022, ...
m=7| 1, 28, 0,  462,  84, 0,   5880,   3360, 210, 0,  63987,  76692,  16632, ...
m=8| 1, 36, 0,  750, 120, 0,  11880,   5940, 330, 0, 159027, 165792,  31812, ...
m=9| 1, 45, 0, 1155, 165, 0,  22275,   9900, 495, 0, 359502, 331617,  57057, ...
   A000217, A001296,A000292,A001297,A027789,A000332,A001298,A293610,A293611, ...
.
m\j| ...    13  14      15       16       17      18      19 20
---|----------------------------------------------------------------
m=0| ...,    0, 0,       0,       0,       0,      0,      0, 0, ...  [A000007]
m=1| ...,    1, 0,       1,      26,      66,     26,      1, 0, ...  [A173018]
m=2| ...,    6, 0,      63,     588,     868,    238,      7, 0, ...  [A062253]
m=3| ...,   21, 0,     966,    5376,    5586,   1176,     28, 0, ...  [A062254]
m=4| ...,   56, 0,    7770,   30660,   24570,   4200,     84, 0, ...  [A062255]
m=5| ...,  126, 0,   42525,  129780,   84630,  12180,    210, 0, ...
m=6| ...,  252, 0,  179487,  446292,  245322,  30492,    462, 0, ...
m=7| ...,  462, 0,  627396, 1315776,  625086,  68376,    924, 0, ...
m=8| ...,  792, 0, 1899612, 3444012, 1440582, 140712,   1716, 0, ...
m=9| ..., 1287, 0, 5135130, 8198190, 3063060, 270270,   3003, 0, ...
          A000389, A112494, A293612, A293613,A293614,A000579.
.
The parameter m runs over the triangles and j indexes the triangles by reading them by rows. Let T(m, n) denote the row [T(m, n, k) for 0 <= k <= n] and T(m) denote the triangle [T(m, n) for n >= 0]. Then for instance T(2) is the triangle A062253, T(4, 2) is row 2 of A062255 (which is [65, 20, 0]) and T(4, 2, 1) = 20.
		

Crossrefs

A000217(n) = T(n, 1, 0), A001296(n) = T(n, 2, 0), A000292(n) = T(n, 2, 1),
A001297(n) = T(n, 3, 0), A027789(n) = T(n, 3, 1), A000332(n) = T(n, 3, 2),
A001298(n) = T(n, 4, 0), A293610(n) = T(n, 4, 1), A293611(n) = T(n, 4, 2),
A000389(n) = T(n, 4, 3), A112494(n) = T(n, 5, 0), A293612(n) = T(n, 5, 1),
A293613(n) = T(n, 5, 2), A293614(n) = T(n, 5, 3), A000579(n) = T(n, 5, 4),
A144969(n) = T(n, 6, 0), A000580(n) = T(n, 6, 5), A000295(n) = T(1, n, 1),
A000460(n) = T(1, n, 2), A000498(n) = T(1, n, 3), A000505(n) = T(1, n, 4),
A000514(n) = T(1, n, 5), A001243(n) = T(1, n, 6), A001244(n) = T(1, n, 7),
A126646(n) = T(2, n, 0), A007820(n) = T(n, n, 0).

Programs

  • Maple
    A293616 := proc(m, n, k) option remember:
    if m = 0 then m^n elif k < 0 or k > n then 0 elif n = 0 then 1 else
    (k+m)*A293616(m,n-1,k) + (n-k)*A293616(m,n-1,k-1) + A293616(m-1,n,k) fi end:
    for m in [$0..4] do for n in [$0..6] do print(seq(A293616(m, n, k), k=0..n)) od od;
    # Sample uses:
    A001298 := n -> A293616(n, 4, 0): A293614 := n -> A293616(n, 5, 3):
    # Flatten:
    a := proc(n) local w; w := proc(k) local t, s; t := 1; s := 1;
    while t <= k do s := s + 1; t := t + s od; [s - 1, s - t + k] end:
    seq(A293616(n - k, w(k)[1], w(k)[2]), k=0..n) end: seq(a(n), n = 0..11);
  • Mathematica
    GenEulerianRow[0, n_] := Table[If[n==0 && j==0,1,0], {j,0,n}];
    GenEulerianRow[m_, n_] := If[n==0,{1},Join[CoefficientList[x^(-m) (1 - x)^(n+m)
        PolyLog[-n-m, m, x] /. Log[1-x] -> 0, x], {0}]];
    (* Sample use: *)
    A173018Row[n_] := GenEulerianRow[1, n]; Table[A173018Row[n], {n, 0, 6}]

Formula

T(m, n, k) = (k + m)*T(m, n-1, k) + (n - k)*T(m, n-1, k-1) + T(m-1, n, k) with boundary conditions T(0, n, k) = 0^n; T(m, n, k) = 0 if k < 0 or k > n; and T(m, 0, k) = 0^k.
Let h(m, n) = x^(-m)*(1 - x)^(n + m)*PolyLog(-n - m, m, x) and p(m, n) the polynomial given by the expansion of h(m, n) after replacing log(1 - x) by 0. Then T(m, n, k) is the k-th coefficient of p(m, n) for 0 <= k < n.

A299807 Rectangular array read by antidiagonals: T(n,k) is the number of distinct sums of k complex n-th roots of 1, n >= 1, k >= 0.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 3, 3, 1, 1, 4, 6, 4, 1, 1, 5, 9, 10, 5, 1, 1, 6, 15, 16, 15, 6, 1, 1, 7, 19, 35, 25, 21, 7, 1, 1, 8, 28, 37, 70, 36, 28, 8, 1, 1, 9, 33, 84, 61, 126, 49, 36, 9, 1, 1, 10, 45, 96, 210, 91, 210, 64, 45, 10, 1, 1, 11, 51, 163, 225, 462, 127, 330, 81, 55, 11, 1, 1, 12, 66, 180, 477, 456, 924, 169, 495, 100, 66
Offset: 1

Views

Author

Max Alekseyev, Feb 24 2018

Keywords

Examples

			Array starts:
  n=1:  1,  1,  1,   1,   1,    1,    1,    1,     1,     1,     1, ...
  n=2:  1,  2,  3,   4,   5,    6,    7,    8,     9,    10,    11, ...
  n=3:  1,  3,  6,  10,  15,   21,   28,   36,    45,    55,    66, ...
  n=4:  1,  4,  9,  16,  25,   36,   49,   64,    81,   100,   121, ...
  n=5:  1,  5, 15,  35,  70,  126,  210,  330,   495,   715,  1001, ...
  n=6:  1,  6, 19,  37,  61,   91,  127,  169,   217,   271,   331, ...
  n=7:  1,  7, 28,  84, 210,  462,  924, 1716,  3003,  5005,  8008, ...
  n=8:  1,  8, 33,  96, 225,  456,  833, 1408,  2241,  3400,  4961, ...
  n=9:  1,  9, 45, 163, 477, 1197, 2674, 5454, 10341, 18469, 31383, ...
  n=10: 1, 10, 51, 180, 501, 1131, 2221, 3951,  6531, 10201, 15231, ...
  ...
		

Crossrefs

Rows: A000012 (n=1), A000027 (n=2), A000217 (n=3), A000290 (n=4), A000332 (n=5), A354343 (n=6), A000579 (n=7), A014820 (n=8).
Columns: A000012 (k=0), A000027 (k=1), A031940 (k=2).
Diagonal: A299754 (n=k).

Formula

From Chai Wah Wu, May 28 2018: (Start)
The following are all conjectures.
For m >= 0, the 2^(m+1)-th row are the figurate numbers based on the 2^m-dimensional regular convex polytope with g.f.: (1+x)^(2^m-1)/(1-x)^(2^m+1).
For p prime, the n=p row corresponds to binomial(k+p-1,p-1) for k = 0,1,2,3,..., which is the maximum possible (i.e., the number of combinations with repetitions of k choices from p categories) with g.f.: 1/(1-x)^p.
(End)

Extensions

Row 6 corrected by Max Alekseyev, Aug 14 2022

A333868 The number of ways to write n as the difference of two k-simplex numbers for k >= 2.

Original entry on oeis.org

1, 3, 3, 4, 5, 4, 3, 6, 7, 4, 4, 4, 5, 9, 4, 4, 5, 5, 7, 9, 4, 4, 4, 6, 4, 7, 7, 4, 7, 5, 3, 6, 6, 11, 9, 4, 4, 6, 4, 4, 6, 4, 5, 11, 5, 4, 4, 6, 6, 6, 5, 4, 7, 12, 8, 6, 4, 4, 6, 4, 4, 8, 5, 8, 9, 4, 4, 7, 8, 4, 5, 4, 5, 8, 4, 8, 9, 4, 5, 8, 4, 6, 10, 7, 4, 6
Offset: 2

Views

Author

Peter Kagey, Apr 08 2020

Keywords

Comments

a(n) >= A001227(n) + A307666(n).
a(n) >= A003016(n) + A003016(n+1) - 2.
Records occur at indices 2, 3, 5, 6, 9, 10, 15, 35, 55, 105, 210, 1365, 2925, 3003,...

Examples

			The a(9) = 6 ways to write 9 as the difference of k-simplex numbers for k > 2 are:
C(5,  2) - C(2, 2) = 10 -  1,
C(6,  2) - C(4, 2) = 15 -  6,
C(10, 2) - C(9, 2) = 45 - 36,
C(5,  3) - C(3, 3) = 10 -  1,
C(9,  8) - C(7, 8) =  9 -  0, and
C(10, 9) - C(9, 9) = 10 -  1,
where C(n,k) = binomial(n,k) = A007318(n,k).
		

Crossrefs

The k-simplex numbers for 2 <= k <= 6 are A000217 (k=2), A000292 (k=3), A000332 (k=4), A000389 (k=5), and A000579 (k=6).

A363174 Array read by rows: T(n,k) is the number of triangles inside a regular n-gon formed by intersecting line segments, considering all configurations of 3 line segments from k distinct vertices, with n >= 3, 3 <= k <= 6.

Original entry on oeis.org

1, 0, 0, 0, 4, 4, 0, 0, 10, 20, 5, 0, 20, 60, 30, 0, 35, 140, 105, 7, 56, 280, 280, 16, 84, 504, 630, 84, 120, 840, 1260, 180, 165, 1320, 2310, 462, 220, 1980, 3960, 796, 286, 2860, 6435, 1716, 364, 4004, 10010, 2856, 455, 5460, 15015, 5005, 560, 7280, 21840, 7744
Offset: 3

Views

Author

Paolo Xausa, May 19 2023

Keywords

Comments

See Sommars and Sommars (1998) for a complete analysis of the problem.

Examples

			Array begins:
  n\k|     3     4     5     6
  ---+---------------------------
   3 |     1,    0,    0,    0;
   4 |     4,    4,    0,    0;
   5 |    10,   20,    5,    0;
   6 |    20,   60,   30,    0;
   7 |    35,  140,  105,    7;
   8 |    56,  280,  280,   16;
   9 |    84,  504,  630,   84;
  10 |   120,  840, 1260,  180;
  ...
		

Crossrefs

Cf. A000579, A006561, A006600 (row sums), A260417.
Cf. A000292 (column k = 3), A033488 (column k = 4), A174002 (column k = 5), A363173 (column k = 6).

Programs

  • Mathematica
    A363174list[rowmax_]:=Module[{d},d[m_,n_]:=Boole[Divisible[n,m]];Table[Binomial[n,k]If[4<=k<=5,k,1]-If[k==6&&EvenQ[n],((1/8n^2-9/8n+7/4)d[2,n]+3/4d[4,n]+(6n-106/3)d[6,n]-33d[12,n]-36d[18,n]-24d[24,n]+96d[30,n]+72d[42,n]+264d[60,n]+96d[84,n]+48d[90,n]+96d[120,n]+48d[210,n])n,0],{n,3,rowmax},{k,3,6}]];A363174list[20]

Formula

T(n,3) = binomial(n,3) = A000292(n-2).
T(n,4) = 4*binomial(n,4) = A033488(n-3).
T(n,5) = 5*binomial(n,5) = A174002(n-4), for n >= 4.
T(n,6) = binomial(n,6) = A000579(n) if n is odd, A000579(n) - A260417(n/2) if n is even.
Sum_{k=3..6} T(n,k) = A006600(n).

A081904 Second binomial transform of binomial(n+6, 6).

Original entry on oeis.org

1, 9, 60, 344, 1794, 8754, 40636, 181380, 784251, 3302451, 13598280, 54922860, 218131380, 853586100, 3296508840, 12581531064, 47510175861, 177681098205, 658665849636, 2422018974096, 8840103322374, 32044237392726, 115417729279620, 413255236888476, 1471500113899311
Offset: 0

Views

Author

Paul Barry, Mar 31 2003

Keywords

Comments

Binomial transform of A055853 (without leading 0).
3rd binomial transform of (1,6,15,20,15,6,1,0,0,0,...).

Crossrefs

Programs

  • Magma
    m:=30; R:=PowerSeriesRing(Integers(), m); Coefficients(R!((1-2*x)^6/(1-3*x)^7)); // G. C. Greubel, Oct 18 2018
  • Mathematica
    LinearRecurrence[{21,-189,945,-2835,5103,-5103,2187}, {1,9,60,344,1794, 8754,40636}, 50] (* G. C. Greubel, Oct 18 2018 *)
  • PARI
    x='x+O('x^30); Vec((1-2*x)^6/(1-3*x)^7) \\ G. C. Greubel, Oct 18 2018
    

Formula

a(n) = 3^n*(n^6 + 93*n^5 + 3055*n^4 + 44055*n^3 + 282424*n^2 + 720132*n + 524880)/524880.
G.f.: (1 - 2*x)^6/(1 - 3*x)^7.
E.g.f.: (720 + 4320*x + 5400*x^2 + 2400*x^3 + 450*x^4 + 36*x^5 + x^6)*exp(3*x) / 720. - G. C. Greubel, Oct 18 2018

A081906 Fourth binomial transform of binomial(n+6, 6).

Original entry on oeis.org

1, 11, 100, 820, 6290, 46006, 324556, 2225060, 14902075, 97873625, 632200000, 4025225000, 25307562500, 157349687500, 968628125000, 5909609375000, 35763408203125, 214838427734375, 1281885742187500, 7601284179687500, 44815856933593750, 262824523925781250, 1533738403320312500
Offset: 0

Views

Author

Paul Barry, Mar 31 2003

Keywords

Comments

Binomial transform of A081905.
5th binomial transform of (1,6,15,20,15,6,1,0,0,0,...).

Crossrefs

Programs

  • Magma
    m:=30; R:=PowerSeriesRing(Integers(), m); Coefficients(R!((1-4*x)^6/(1-5*x)^7)); // G. C. Greubel, Oct 17 2018
  • Mathematica
    LinearRecurrence[{35, -525, 4375, -21875, 65625, -109375, 78125}, {1, 11, 100, 820, 6290, 46006, 324556}, 50] (* G. C. Greubel, Oct 17 2018 *)
  • PARI
    x='x+O(x^30); Vec((1-4*x)^6/(1-5*x)^7) \\ G. C. Greubel, Oct 17 2018
    

Formula

a(n) = 5^n*(n^6 + 165*n^5 + 9535*n^4 + 238575*n^3 + 2590024*n^2 + 10661700*n + 11250000)/11250000.
G.f.: (1-4*x)^6/(1-5*x)^7.
E.g.f.: (720 + 4320*x + 5400*x^2 + 2400*x^3 + 450*x^4 + 36*x^5 + x^6)*exp(5*x) / 720. - G. C. Greubel, Oct 17 2018

A096944 Seventh column of (1,5)-Pascal triangle A096940.

Original entry on oeis.org

5, 31, 112, 308, 714, 1470, 2772, 4884, 8151, 13013, 20020, 29848, 43316, 61404, 85272, 116280, 156009, 206283, 269192, 347116, 442750, 559130, 699660, 868140, 1068795, 1306305, 1585836, 1913072, 2294248, 2736184, 3246320, 3832752
Offset: 0

Views

Author

Wolfdieter Lang, Jul 16 2004

Keywords

Comments

If Y is a 5-subset of an n-set X then, for n>=10, a(n-10) is the number of 6-subsets of X having at most one element in common with Y. > - Milan Janjic, Dec 08 2007

Crossrefs

Sixth column: A096943; eighth column: A096945.

Formula

G.f.: (5-4*x)/(1-x)^7.
a(n)= (n+30)*binomial(n+5, 5)/6 = 5*b(n)-4*b(n-1), with b(n):=A000579(n+6)=binomial(n+6, 6).

A103604 a(n) = binomial(n+6,6) * binomial(n+10,6).

Original entry on oeis.org

210, 3234, 25872, 144144, 630630, 2312310, 7399392, 21237216, 55747692, 135795660, 310390080, 671571264, 1385115732, 2738894004, 5216940960, 9610154400, 17178150990, 29881321470, 50707697040, 84126042000, 136704818250, 217946538810, 341398774080, 526116951360
Offset: 0

Views

Author

Zerinvary Lajos, Apr 22 2005

Keywords

Crossrefs

Programs

  • Magma
    A103604:= func< n | Binomial(n+6,6)*Binomial(n+10,6) >;
    [A103604(n): n in [0..30]]; // G. C. Greubel, Mar 05 2025
    
  • Mathematica
    Table[Binomial[n+6,6]Binomial[n+10,6],{n,0,30}] (* or *) LinearRecurrence[ {13,-78,286,-715,1287,-1716,1716,-1287,715,-286,78,-13,1},{210,3234,25872, 144144,630630,2312310,7399392,21237216,55747692,135795660,310390080, 671571264,1385115732},30] (* Harvey P. Dale, Apr 18 2019 *)
  • PARI
    a(n) = binomial(n+6,6)*binomial(n+10,6) \\ Colin Barker, Jul 01 2015
    
  • PARI
    Vec(-42*(5*x^2+12*x+5)/(x-1)^13 + O(x^30)) \\ Colin Barker, Jul 01 2015
    
  • SageMath
    def A103604(n): return binomial(n+6,6)*binomial(n+10,6)
    print([A103604(n) for n in range(31)]) # G. C. Greubel, Mar 05 2025

Formula

G.f.: 42*(5+12*x+5*x^2) / (1-x)^13. - Colin Barker, Jul 01 2015
a(n) = A000579(n+6)*A000579(n+10). - Michel Marcus, Jul 01 2015
From Amiram Eldar, Sep 06 2022: (Start)
Sum_{n>=0} 1/a(n) = 60*Pi^2 - 10445899/17640.
Sum_{n>=0} (-1)^n/a(n) = 447173/2205 - 2048*log(2)/7. (End)
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