A154372
Triangle T(n,k) = (k+1)^(n-k)*binomial(n,k).
Original entry on oeis.org
1, 1, 1, 1, 4, 1, 1, 12, 9, 1, 1, 32, 54, 16, 1, 1, 80, 270, 160, 25, 1, 1, 192, 1215, 1280, 375, 36, 1, 1, 448, 5103, 8960, 4375, 756, 49, 1, 1, 1024, 20412, 57344, 43750, 12096, 1372, 64, 1
Offset: 0
With the array M(k) as defined in the Comments section, the infinite product M(0)*M(1)*M(2)*... begins
/1 \ /1 \ /1 \ /1 \
|1 1 ||0 1 ||0 1 | |1 1 |
|1 3 1 ||0 1 1 ||0 0 1 |... = |1 4 1 |
|1 6 5 1 ||0 1 3 1 ||0 0 1 1 | |1 12 9 1|
|... ||0 1 6 5 1 ||0 0 1 3 1| |... |
|... ||... ||... | | |
- _Peter Bala_, Jan 13 2015
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/* As triangle */ [[(k+1)^(n-k)*Binomial(n,k) : k in [0..n]]: n in [0.. 15]]; // Vincenzo Librandi, Sep 15 2016
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T[n_, k_] := (k + 1)^(n - k)*Binomial[n, k]; Table[T[n, k], {n, 0, 10}, {k, 0, n}] // Flatten (* G. C. Greubel, Sep 15 2016 *)
A217629
Triangle, read by rows, where T(n,k) = k!*C(n, k)*3^(n-k) for n>=0, k=0..n.
Original entry on oeis.org
1, 3, 1, 9, 6, 2, 27, 27, 18, 6, 81, 108, 108, 72, 24, 243, 405, 540, 540, 360, 120, 729, 1458, 2430, 3240, 3240, 2160, 720, 2187, 5103, 10206, 17010, 22680, 22680, 15120, 5040, 6561, 17496, 40824, 81648, 136080, 181440, 181440, 120960, 40320
Offset: 0
Triangle begins:
1;
3, 1;
9, 6, 2;
27, 27, 18, 6;
81, 108, 108, 72, 24;
243, 405, 540, 540, 360, 120;
729, 1458, 2430, 3240, 3240, 2160, 720;
2187, 5103, 10206, 17010, 22680, 22680, 15120, 5040;
6561, 17496, 40824, 81648, 136080, 181440, 181440, 120960, 40320; etc.
-
[Factorial(n)/Factorial(n-k)*3^(n-k): k in [0..n], n in [0..10]];
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Flatten[Table[n!/(n-k)!*3^(n-k), {n, 0, 10}, {k, 0, n}]]
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
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;
...
- Shara Lalo and Zagros Lalo, Polynomial Expansion Theorems and Number Triangles, Zana Publishing, 2018, ISBN: 978-1-9995914-0-3.
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).
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[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
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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
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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
A094796
Triangle read by rows giving coefficients of polynomials arising in successive differences of central binomial numbers.
Original entry on oeis.org
1, 3, 1, 9, 15, 6, 27, 108, 135, 42, 81, 594, 1539, 1530, 456, 243, 2835, 12555, 25245, 22122, 6120, 729, 12393, 83835, 281475, 482436, 383292, 101520, 2187, 51030, 489888, 2466450, 6916833, 10546200, 7786692, 1980720
Offset: 0
The third differences of the central binomial numbers are given by D_3(n) = binomial(2*n,n)*(n+1)*(n+2)*(n+3)*(27*n^3 + 108*n^2 + 135*n + 42) and the fourth row of the triangle is 27, 108, 135, 42.
From _M. F. Hasler_, Nov 15 2019: (Start)
The table reads:
n | row(n)
0 | 1
1 | 3 1
2 | 9 15 6
3 | 27 108 135 42
4 | 81 594 1539 1530 456
5 | 243 2835 12555 25245 22122 6120
6 | 729 12393 83835 281475 482436 383292 101520
7 | 2187 51030 489888 2466450 6916833 10546200 7786692 1980720
8 | 6561 201204 2602530 18329976 75981969 186899076 260520300 181218384 44634240
(End)
Cf.
A000984 (central binomial coefficients),
A163771 (square array of central binomial coefficients and higher differences),
A000244 (column k=0).
-
Dnk := proc(n,k)
option remember;
if k < 0 then
0 ;
elif k = 0 then
binomial(2*n,n) ;
else
procname(n+1,k-1)-procname(n,k-1) ;
end if;
end proc:
A094796 := proc(n,k)
local xyvec,i,x ;
xyvec := [] ;
for i from 0 to n do
xyvec := [op(xyvec),[i,Dnk(i,n)*mul(i+j,j=1..n)/Dnk(i,0)]] ;
end do:
CurveFitting[PolynomialInterpolation](xyvec,x) ;
coeff(%,x,n-k) ;
end proc: # R. J. Mathar, Nov 19 2019
-
Dnk[n_, k_] := Dnk[n, k] = Which[k < 0, 0, k == 0, Binomial[2*n, n], True, Dnk[n + 1, k - 1] - Dnk[n, k - 1]];
T[n_, k_] := Module[{xyvec, i, x , ip}, xyvec = {}; For[i = 0, i <= n, i++, AppendTo[xyvec, {i, Dnk[i, n]*Product[i + j, {j, 1, n}]/Dnk[i, 0]}]]; ip = InterpolatingPolynomial[xyvec, x]; Coefficient[ip, x, n - k]];
Table[T[n, k], {n, 0, 8}, {k, 0, n}] // Flatten (* Jean-François Alcover, Apr 01 2024, after R. J. Mathar *)
-
apply( {A094796_row(n,D(n,k)=if(k,D(n+1,k-1)-D(n,k-1),binomial(2*n,n)))=Vec(polinterpolate([0..n],vector(n+1,k,D(k--,n)*(n+k)!/k!/binomial(2*k,k))))}, [0..8]) \\ M. F. Hasler, Nov 15 2019
A082149
A transform of C(n,2).
Original entry on oeis.org
0, 0, 1, 6, 30, 140, 615, 2562, 10220, 39384, 147645, 541310, 1948650, 6908772, 24180611, 83702010, 286978200, 975725744, 3293074233, 11041484022, 36804946550, 122037454140, 402723598431, 1323234680306, 4330586226180
Offset: 0
-
[Binomial(n,2)*(1 + 3^(n-2))/2: n in [0..30]]; // G. C. Greubel, Feb 10 2018
-
CoefficientList[Series[(x^2/(1-3*x)^3 + x^2/(1-x)^3)/2, {x,0,50}], x] (* or *) Table[Binomial[n,2]*(1 + 3^(n-2))/2, {n,0,30}] (* G. C. Greubel, Feb 10 2018 *)
LinearRecurrence[{12,-57,136,-171,108,-27},{0,0,1,6,30,140},30] (* Harvey P. Dale, Aug 11 2021 *)
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for(n=0,30, print1(binomial(n,2)*(1 + 3^(n-2))/2, ", ")) \\ G. C. Greubel, Feb 10 2018
A082151
A transform of C(n,2).
Original entry on oeis.org
0, 0, 1, 12, 102, 760, 5295, 35364, 228956, 1445616, 8936685, 54252220, 324214242, 1911205608, 11132579003, 64170616020, 366497915640, 2076171038176, 11676266706969, 65242364726124, 362433045180830, 2002838101907160, 11015341078090503, 60321223747375492
Offset: 0
-
[Binomial(n,2)*(3^(n-2) + 5^(n-2))/2: n in [0..30]]; // G. C. Greubel, Feb 10 2018
-
CoefficientList[Series[(x^2/(1-5*x)^3 + x^2/(1-3*x)^3)/2, {x,0,50}], x] (* or *) Table[Binomial[n,2]*(3^(n-2) + 5^(n-2))/2, {n,0,30}] (* G. C. Greubel, Feb 10 2018 *)
LinearRecurrence[{24,-237,1232,-3555,5400,-3375},{0,0,1,12,102,760},30] (* Harvey P. Dale, Apr 10 2023 *)
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for(n=0,30, print1(binomial(n,2)*(3^(n-2) + 5^(n-2))/2, ", ")) \\ G. C. Greubel, Feb 10 2018
A116138
a(n) = 3^n * n*(n + 1).
Original entry on oeis.org
0, 6, 54, 324, 1620, 7290, 30618, 122472, 472392, 1771470, 6495390, 23383404, 82904796, 290166786, 1004423490, 3443737680, 11708708112, 39516889878, 132497807238, 441659357460, 1464449448420, 4832683179786, 15878816162154
Offset: 0
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List([0..30], n-> 3^n*n*(n+1)); # G. C. Greubel, May 10 2019
-
[(n^2+n)*3^n: n in [0..30]]; // Vincenzo Librandi, Feb 28 2013
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I:=[0,6,54]; [n le 3 select I[n] else 9*Self(n-1)-27*Self(n-2)+27*Self(n-3): n in [1..30]]; // Vincenzo Librandi, Feb 28 2013
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Table[(n^2 + n) 3^n, {n, 0, 30}] (* Vincenzo Librandi, Feb 28 2013 *)
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a(n)=(n^2+n)*3^n \\ Charles R Greathouse IV, Feb 28 2013
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[3^n*n*(n+1) for n in (0..30)] # G. C. Greubel, May 10 2019
Original entry on oeis.org
1, 13, 94, 526, 2551, 11299, 47020, 186988, 718429, 2686729, 9831658, 35340826, 125154355, 437641663, 1513809688, 5187129880, 17627632249, 59469045061, 199327841590, 664232428390, 2201904349231, 7264715299483, 23865295832644, 78091766836996
Offset: 1
- "Supplemento al Periodico di Matematica", Raffaello Giusti Editore (Livorno) - Apr / May, 1913 - p. 99 (Problem 1277, case x=3).
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[(3^n*(n^2-n+1)-1)/2: n in [1..25]]; // Vincenzo Librandi, Aug 19 2013
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CoefficientList[Series[(1 + 3 x) / ((1 - x) (1 - 3 x)^3), {x, 0, 25}], x] (* Vincenzo Librandi, Aug 19 2013 *)
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a(n) = (3^n*(n^2-n+1)-1)/2 \\ Michel Marcus, Jun 07 2013
A367591
Expansion of 1/((1-x) * (1-3*x)^3).
Original entry on oeis.org
1, 10, 64, 334, 1549, 6652, 27064, 105796, 401041, 1483606, 5380840, 19198306, 67559437, 234963352, 808919632, 2760370984, 9346519297, 31429487170, 105039380080, 349114288150, 1154561484781, 3801030845140, 12462203297224, 40705156945324, 132494756301649
Offset: 0
A126177
Triangle read by rows: T(n,k) is number of hex trees with n edges and k leaves (n >= 1, 1 <= k <= 1 + floor(n/2)).
Original entry on oeis.org
3, 9, 1, 27, 9, 81, 54, 2, 243, 270, 30, 729, 1215, 270, 5, 2187, 5103, 1890, 105, 6561, 20412, 11340, 1260, 14, 19683, 78732, 61236, 11340, 378, 59049, 295245, 306180, 85050, 5670, 42, 177147, 1082565, 1443420, 561330, 62370, 1386, 531441, 3897234
Offset: 1
Triangle starts:
3;
9, 1;
27, 9;
81, 54, 2;
243, 270, 30;
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T:=(n,k)->3^(n-2*k+2)*binomial(2*k-2,k-1)*binomial(n,2*k-2)/k: for n from 1 to 13 do seq(T(n,k),k=1..1+floor(n/2)) od; # yields sequence in triangular form
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