A176992
Triangle T(n,m) = binomial(2n-k+1, n+1) read by rows, 0 <= k <= n.
Original entry on oeis.org
1, 3, 1, 10, 4, 1, 35, 15, 5, 1, 126, 56, 21, 6, 1, 462, 210, 84, 28, 7, 1, 1716, 792, 330, 120, 36, 8, 1, 6435, 3003, 1287, 495, 165, 45, 9, 1, 24310, 11440, 5005, 2002, 715, 220, 55, 10, 1, 92378, 43758, 19448, 8008, 3003, 1001, 286, 66, 11, 1, 352716, 167960, 75582, 31824, 12376, 4368, 1365, 364, 78, 12, 1
Offset: 0
Triangle begins:
1;
3, 1;
10, 4, 1;
35, 15, 5, 1;
126, 56, 21, 6, 1;
462, 210, 84, 28, 7, 1;
1716, 792, 330, 120, 36, 8, 1;
6435, 3003, 1287, 495, 165, 45, 9, 1;
24310, 11440, 5005, 2002, 715, 220, 55, 10, 1;
92378, 43758, 19448, 8008, 3003, 1001, 286, 66, 11, 1;
352716, 167960, 75582, 31824, 12376, 4368, 1365, 364, 78, 12, 1;
-
/* As triangle */ [[Binomial(2*n-k+1,n+1): k in [0..n]]: n in [0.. 10]]; // Vincenzo Librandi, Jul 12 2015
-
A176992 := proc(n,k) binomial(1+2*n-k,n+1) ; end proc: # R. J. Mathar, Dec 09 2010
-
p[t_, j_] = ((-1)^(j + 1)/2)*Sum[Binomial[k - j - 1, j + 1]*t^k, {k, 0, Infinity}];
Flatten[Table[CoefficientList[ExpandAll[p[t, j]], t], {j, 0, 10}]]
A213808
Triangle of numbers C^(7)(n,k) of combinations with repetitions from n different elements over k for each of them not more than 7 appearances allowed.
Original entry on oeis.org
1, 1, 1, 1, 2, 3, 1, 3, 6, 10, 1, 4, 10, 20, 35, 1, 5, 15, 35, 70, 126, 1, 6, 21, 56, 126, 252, 462, 1, 7, 28, 84, 210, 462, 924, 1716, 1, 8, 36, 120, 330, 792, 1716, 3432, 6427, 1, 9, 45, 165, 495, 1287, 3003, 6435, 12861, 24229, 1, 10, 55, 220, 715, 2002, 5005, 11440, 24300, 48520, 91828
Offset: 0
Triangle begins
n/k | 0 1 2 3 4 5 6 7 8
----+---------------------------------------------------
0 | 1
1 | 1 1
2 | 1 2 3
3 | 1 3 6 10
4 | 1 4 10 20 35
5 | 1 5 15 35 70 126
6 | 1 6 21 56 126 252 462
7 | 1 7 28 84 210 462 924 1716
8 | 1 8 36 120 330 792 1716 3432 6427
Cf.
A007318,
A005725,
A059481,
A111808,
A187925,
A213742,
A213743,
A213744,
A000217,
A000292,
A000332,
A000389,
A000579,
A000580.
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Table[Sum[(-1)^r*Binomial[n, r]*Binomial[n - 8*r + k - 1, n - 1], {r, 0, Floor[k/8]}], {n, 0, 10}, {k, 0, n}] // Flatten (* G. C. Greubel, Nov 25 2017 *)
-
for(n=0,10, for(k=0,n, print1(if(n==0 && k==0, 1, sum(r=0, floor(k/8), (-1)^r*binomial(n,r)*binomial(n-8*r + k-1,n-1))), ", "))) \\ G. C. Greubel, Nov 25 2017
A130746
Triangle read by rows: T(n,m) = binomial(n+m,1+n), 1<=m<=n.
Original entry on oeis.org
1, 1, 4, 1, 5, 15, 1, 6, 21, 56, 1, 7, 28, 84, 210, 1, 8, 36, 120, 330, 792, 1, 9, 45, 165, 495, 1287, 3003, 1, 10, 55, 220, 715, 2002, 5005, 11440, 1, 11, 66, 286, 1001, 3003, 8008, 19448, 43758, 1, 12, 78, 364, 1365, 4368, 12376, 31824, 75582, 167960
Offset: 1
1;
1, 4;
1, 5, 15;
1, 6, 21, 56;
1, 7, 28, 84, 210;
1, 8, 36, 120, 330, 792;
1, 9, 45, 165, 495, 1287, 3003;
1, 10, 55, 220, 715, 2002, 5005, 11440;
-
Table[Table[Binomial[n + i, i + 1], {n, 1, i}], {i, 1, 10}] Flatten[%]
A174952
Triangle t(n,m)= binomial(n+m-1,n-1) + binomial(2*n-m-1,n-1) -binomial(2*n-1,n-1) read by rows, 0<=m<=n.
Original entry on oeis.org
1, 1, 1, 1, 1, 1, 1, -1, -1, 1, 1, -11, -15, -11, 1, 1, -51, -76, -76, -51, 1, 1, -204, -315, -350, -315, -204, 1, 1, -785, -1226, -1422, -1422, -1226, -785, 1, 1, -2995, -4683, -5523, -5775, -5523, -4683, -2995, 1, 1, -11431, -17830, -21142, -22528, -22528
Offset: 0
1;
1, 1;
1, 1, 1;
1, -1, -1, 1;
1, -11, -15, -11, 1;
1, -51, -76, -76, -51, 1;
1 -204, -315, -350, -315, -204, 1;
1, -785, -1226, -1422, -1422, -1226, -785, 1;
1, -2995, -4683, -5523, -5775, -5523, -4683, -2995, 1;
1, -11431, -17830, -21142, -22528, -22528, -21142, -17830, -11431, 1;
1, -43748, -68013, -80718, -86658, -88374, -86658, -80718, -68013, -43748, 1;
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A174952 := proc(n,m)
binomial(n+m-1,n-1)+binomial(2*n-m-1,n-1) -binomial(2*n-1,n-1);
end proc: # R. J. Mathar, Jan 15 2013
Definition corrected and deobfuscated.
R. J. Mathar, Jan 15 2013
A343936
Number of ways to choose a multiset of n divisors of n - 1.
Original entry on oeis.org
1, 2, 3, 10, 5, 56, 7, 120, 45, 220, 11, 4368, 13, 560, 680, 3876, 17, 26334, 19, 42504, 1771, 2024, 23, 2035800, 325, 3276, 3654, 201376, 29, 8347680, 31, 376992, 6545, 7140, 7770, 145008513, 37, 9880, 10660, 53524680, 41, 73629072, 43, 1712304, 1906884
Offset: 1
The a(1) = 1 through a(5) = 5 multisets:
{} {1} {1,1} {1,1,1} {1,1,1,1}
{2} {1,3} {1,1,2} {1,1,1,5}
{3,3} {1,1,4} {1,1,5,5}
{1,2,2} {1,5,5,5}
{1,2,4} {5,5,5,5}
{1,4,4}
{2,2,2}
{2,2,4}
{2,4,4}
{4,4,4}
The a(6) = 56 multisets:
11111 11136 11333 12236 13366 22266 23666
11112 11166 11336 12266 13666 22333 26666
11113 11222 11366 12333 16666 22336 33333
11116 11223 11666 12336 22222 22366 33336
11122 11226 12222 12366 22223 22666 33366
11123 11233 12223 12666 22226 23333 33666
11126 11236 12226 13333 22233 23336 36666
11133 11266 12233 13336 22236 23366 66666
The version for chains of divisors is
A163767.
Choosing n divisors of n gives
A343935.
A007318 counts k-sets of elements of {1..n}.
A009998 = n^k (as an array, offset 1).
A059481 counts k-multisets of elements of {1..n}.
A146291 counts divisors of n with k prime factors (with multiplicity).
A253249 counts nonempty chains of divisors of n.
Strict chains of divisors:
-
A067824 counts strict chains of divisors starting with n.
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A074206 counts strict chains of divisors from n to 1.
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A251683 counts strict length k + 1 chains of divisors from n to 1.
-
A334996 counts strict length-k chains of divisors from n to 1.
-
A337255 counts strict length-k chains of divisors starting with n.
-
A337256 counts strict chains of divisors of n.
-
A343662 counts strict length-k chains of divisors.
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multchoo[n_,k_]:=Binomial[n+k-1,k];
Table[multchoo[DivisorSigma[0,n],n-1],{n,50}]
A241188
Triangle T(n,s) of Dynkin type D_n read by rows (n >= 2, 0 <= s <= n).
Original entry on oeis.org
1, 2, 1, 1, 3, 5, 5, 1, 4, 9, 16, 20, 1, 5, 14, 30, 55, 77, 1, 6, 20, 50, 105, 196, 294, 1, 7, 27, 77, 182, 378, 714, 1122, 1, 8, 35, 112, 294, 672, 1386, 2640, 4290, 1, 9, 44, 156, 450, 1122, 2508, 5148, 9867, 16445
Offset: 2
Triangle begins:
1, 2, 1,
1, 3, 5, 5,
1, 4, 9, 16, 20,
1, 5, 14, 30, 55, 77,
1, 6, 20, 50, 105, 196, 294,
1, 7, 27, 77, 182, 378, 714, 1122,
1, 8, 35, 112, 294, 672, 1386, 2640, 4290,
1, 9, 44, 156, 450, 1122, 2508, 5148, 9867, 16445,
...
- M. A. A. Obaid, S. K. Nauman, W. M. Fakieh, C. M. Ringel, The numbers of support-tilting modules for a Dynkin algebra, 2014.
- M. A. A. Obaid, S. K. Nauman, W. M. Fakieh, C. M. Ringel, The numbers of support-tilting modules for a Dynkin algebra, arXiv:1403.5827 [math.RT], 2014 and J. Int. Seq. 18 (2015) 15.10.6.
See
A009766 for the case of type A.
See
A059481 for the case of type B/C.
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f[t_, s_] := Binomial[t, s] (s + t)/t;
T[, 0] = 1; T[n, n_] := f[2 n - 2, n - 2]; T[n_, s_] := f[n + s - 2, s];
Table[T[n, s], {n, 2, 9}, {s, 0, n}] // Flatten (* Jean-François Alcover, Feb 12 2019 *)
A316140
Denominator of the autosequence 2/((n+2)*(n+3)) difference table written by antidiagonals.
Original entry on oeis.org
3, 6, 6, 10, 15, 10, 15, 30, 30, 15, 21, 105, 70, 105, 21, 28, 84, 140, 140, 84, 28, 36, 126, 252, 315, 252, 126, 36, 45, 180, 420, 630, 630, 420, 180, 45, 55, 495, 660, 1155, 1386, 1155, 660, 495, 55, 66, 330
Offset: 0
Difference table:
1/3, 1/6, 1/10, 1/15, ...
-1/6, -1/15, -1/30, -2/105, ...
1/10, 1/30, 1/70, 1/140, ...
-1/15, -2/105, -1/140, -1/315, ... .
...
Table starts:
3 6 10 15 21 28 ...
6 15 30 105 84 126 ...
10 30 70 140 252 420 ...
15 105 140 315 630 1155 ...
21 84 252 630 1386 2772 ...
...
As a triangle:
3;
6, 6;
10, 15, 10;
15, 30, 30, 15;
...
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tabl(nn) = {nn = 2*nn; m = matrix(nn, nn, n, k, if (n==1, 2/((k+1)*(k+2)))); for (n=2, nn, for (k=1, nn-n +1, m[n, k] = m[n-1, k+1] - m[n-1,k];);); nn = nn/2; matrix(nn, nn, n, k, denominator(m[n,k]));} \\ Michel Marcus, Jul 05 2018
Comments