A198400
a(n) = 10^n - 10*n.
Original entry on oeis.org
1, 0, 80, 970, 9960, 99950, 999940, 9999930, 99999920, 999999910, 9999999900, 99999999890, 999999999880, 9999999999870, 99999999999860, 999999999999850, 9999999999999840, 99999999999999830, 999999999999999820, 9999999999999999810, 99999999999999999800, 999999999999999999790
Offset: 0
A189711
Number of non-monotonic functions from [k] to [n-k].
Original entry on oeis.org
2, 10, 8, 28, 54, 22, 60, 190, 204, 52, 110, 490, 916, 676, 114, 182, 1050, 2878, 3932, 2118, 240, 280, 1988, 7278, 15210, 16148, 6474, 494, 408, 3444, 15890, 45738, 77470, 65210, 19576, 1004, 570, 5580, 31192, 115808, 278358, 389640, 261708, 58920, 2026, 770, 8580, 56484, 258720, 820118, 1677048, 1951700, 1048008, 176994, 4072, 1012, 12650, 96006, 525444, 2090296, 5758802, 10073698, 9763628, 4193580, 531262, 8166
Offset: 5
Triangle T(n,k) begins
n\k 3 4 5 6 7 8 9
5 2
6 10 8
7 28 54 22
8 60 190 204 52
9 110 490 916 676 114
10 182 1050 2878 3932 2118 240
11 280 1988 7278 15210 16148 6474 494
...
For n=6 and k=4, T(6,4)=8 since there are 8 non-monotonic functions f from [4] to [2], namely, f = <f(1),f(2),f(3),f(4)> given by <1,1,2,1>, <1,2,1,1>, <1,2,2,1>, <1,2,1,2>, <2,2,1,2>, <2,1,2,2>, <2,1,1,2>, and <2,1,2,1>.
-
a189711 n k = (n - k) ^ k - 2 * a007318 (n - 1) k + n - k
a189711_row n = map (a189711 n) [3..n-2]
a189711_tabl = map a189711_row [5..]
-- Reinhard Zumkeller, May 16 2014
-
seq(seq((n-k)^k-2*binomial(n-1,k)+(n-k),k=3..(n-2)),n=5..15);
-
nmax = 15; t[n_, k_] := (n-k)^k-2*Binomial[n-1, k]+(n-k); Flatten[ Table[ t[n, k], {n, 5, nmax}, {k, 3, n-2}]](* Jean-François Alcover, Nov 18 2011, after Maple *)
A192020
Triangle read by rows: T(n,k) is the number of unordered pairs of nodes at distance k in the binomial tree of order n (1 <= k <= 2n-1; entries in row n are the coefficients of the corresponding Wiener polynomial).
Original entry on oeis.org
1, 3, 2, 1, 7, 8, 8, 4, 1, 15, 22, 31, 28, 17, 6, 1, 31, 52, 90, 112, 104, 68, 30, 8, 1, 63, 114, 225, 344, 418, 388, 270, 136, 47, 10, 1, 127, 240, 516, 908, 1331, 1568, 1464, 1064, 589, 240, 68, 12, 1, 255, 494, 1123, 2180, 3663, 5138, 5931, 5560, 4181, 2482, 1137, 388, 93, 14, 1
Offset: 0
T(2,1)=3, T(2,2)=2, T(2,3)=1 because the binomial tree b(2) is basically the path tree A-B-R-C and we have 3 (AB, BR, RC), 2 (AR, BC), and 1 (AC) pairs of nodes at distances 1, 2, and 3, respectively.
Triangle starts:
1;
3, 2, 1;
7, 8, 8, 4, 1;
15, 22, 31, 28, 17, 6, 1;
31, 52, 90, 112, 104, 68, 30, 8, 1;
- K. Viswanathan Iyer and K. R. Udaya Kumar Reddy, Wiener index of Binomial trees and Fibonacci trees, Int'l. J. Math. Engin. with Comp., Accepted for publication, Sept. 2009.
- T. H. Cormen, C. E. Leiserson and R. L. Rivest: Introduction to Algorithms. MIT Press / McGraw-Hill (1990).
-
G := 1/(1-z-t*z): Gser := simplify(series(G, z = 0, 11)): for n from 0 to 8 do r[n] := sort(coeff(Gser, z, n)) end do: w[0] := 0: for n to 8 do w[n] := sort(expand(2*w[n-1]+t*r[n-1]^2)) end do: for n to 8 do seq(coeff(w[n], t, k), k = 1 .. 2*n-1) end do; # yields sequence in triangular form
-
max = 8; g = 1/(1 - z - t*z); r = CoefficientList[ Series[g, {z, 0, max}], z]; w[0] = 0; w[n_] := w[n] = 2 w[n-1] + t*r[[n]]^2; Flatten[ Table[ Drop[ CoefficientList[ w[n], t], 1], {n, 1, max}]] (* Jean-François Alcover, Oct 06 2011, after Maple *)
-
a(n) = my(s=sqrtint(n),r=n-s^2); sum(i=0,s, 2^(s-i)*binomial(2*i,r)); \\ Kevin Ryde, Sep 13 2019
A271698
Triangle read by rows, T(n,k) = Sum_{j=0..n} C(-j,-n)*E1(j,k), E1 the Eulerian numbers A173018, for n>=0 and 0<=k<=n.
Original entry on oeis.org
1, 1, 0, 0, 1, 0, 0, 2, 1, 0, 0, 2, 8, 1, 0, 0, 2, 28, 22, 1, 0, 0, 2, 72, 182, 52, 1, 0, 0, 2, 164, 974, 864, 114, 1, 0, 0, 2, 352, 4174, 8444, 3474, 240, 1, 0, 0, 2, 732, 15782, 61464, 57194, 12660, 494, 1, 0, 0, 2, 1496, 55286, 373940, 660842, 332528, 43358, 1004, 1, 0
Offset: 0
Triangle starts:
1,
1, 0,
0, 1, 0,
0, 2, 1, 0,
0, 2, 8, 1, 0,
0, 2, 28, 22, 1, 0,
0, 2, 72, 182, 52, 1, 0,
0, 2, 164, 974, 864, 114, 1, 0
-
A271698 := (n,k) -> add(binomial(-j,-n)*combinat:-eulerian1(j,k), j=0..n):
seq(seq(A271698(n, k), k=0..n), n=0..10);
-
<
A353047
Number of length n words on alphabet {0,1,2} that contain each of the subwords 01, 02, 10, 12, 20, and 21 as (not necessarily contiguous) subwords.
Original entry on oeis.org
12, 108, 600, 2664, 10404, 37476, 127920, 420768, 1348476, 4242204, 13169160, 40490712, 123635028, 375623892, 1137095520, 3433306896, 10347106860, 31141984140, 93639862200, 281372571720, 845074016772, 2537235316548, 7615933808400, 22856659795584, 68588501433564
Offset: 5
a(5) = 12 because we have: {0, 1, 2, 0, 1}, {0, 1, 2, 1, 0}, {0, 2, 1, 0, 2}, {0, 2, 1, 2, 0}, {1, 0, 2, 0, 1}, {1, 0, 2, 1, 0}, {1, 2, 0, 1, 2}, {1, 2, 0, 2, 1}, {2, 0, 1, 0, 2}, {2, 0, 1, 2, 0}, {2, 1, 0, 1, 2}, {2, 1, 0, 2, 1}.
-
nn = 15; vertices = Level[Outer[ List, {a, b, c}, {d, e, f}, {h, i, j}, {k, l, m}, {n, o, p}, {q, r, s}], {6}]; x = {a -> b, d -> e, i -> j, o -> p}; y = {b -> c, h -> i, k -> l, r -> s}; z = {e -> f, l -> m, n -> o, q -> r}; replacementlist = Table[vertices[[kk]] -> kk, {kk, 1, 729}]; G= Normal[SparseArray[Flatten[Table[Normal[Merge[ Map[{mm, vertices[[mm]] /. # /. replacementlist} -> 1 &, {x, y, z}], Total]], {mm, 1, 729}]]]]; Iwg =
Inverse[IdentityMatrix[729] - w G]; CoefficientList[ Series[Iwg[[1, 729]], {w, 0, nn}], w]
A146749
Coefficients of the Pascal sequence minus the Eulerian numbers: q(x,n)= = (1 - x)^(n + 1)*PolyLog[ -n, x]; p(x,n) = (q(x, n)/x - (x + 1)^(n - 1))/x.
Original entry on oeis.org
2, 8, 8, 22, 60, 22, 52, 292, 292, 52, 114, 1176, 2396, 1176, 114, 240, 4272, 15584, 15584, 4272, 240, 494, 14580, 88178, 156120, 88178, 14580, 494, 1004, 47804, 455108, 1310228, 1310228, 455108, 47804, 1004
Offset: 3
Triangle begins:
{2},
{8, 8},
{22, 60, 22},
{52, 292, 292, 52},
{114, 1176, 2396, 1176, 114},
{240, 4272, 15584, 15584, 4272, 240},
{494, 14580, 88178, 156120, 88178, 14580, 494},
{1004, 47804, 455108, 1310228, 1310228, 455108, 47804, 1004}
...
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q[x_, n_] = (1 - x)^(n + 1)*PolyLog[ -n, x]; p[x_, n_] = (q[x, n]/x - (x + 1)^(n - 1))/x; Table[CoefficientList[FullSimplify[ExpandAll[p[x, n]]], x], {n, 3, 10}]; Flatten[%]
A146750
Coefficients of the Pascal sequence minus the Eulerian numbers with first and last columns subtracted: f(n)=2^n - 2n; q(x,n)= = (1 - x)^(n + 1)*PolyLog[ -n, x]; p(x,n) = ((q(x, n)/x - (x + 1)^(n - 1))/x - f[n] - f[n]*x^(n - 3))/x.
Original entry on oeis.org
60, 292, 292, 1176, 2396, 1176, 4272, 15584, 15584, 4272, 14580, 88178, 156120, 88178, 14580, 47804, 455108, 1310228, 1310228, 455108, 47804
Offset: 5
{2}, {8, 8}, {22, 60, 22}, {52, 292, 292, 52}, {114, 1176, 2396, 1176, 114}, {240, 4272, 15584, 15584, 4272, 240}, {494, 14580, 88178, 156120, 88178, 14580, 494}, {1004, 47804, 455108, 1310228, 1310228, 455108, 47804, 1004}
-
f[n_] = 2^n - 2n; q[x_, n_] = (1 - x)^(n + 1)*PolyLog[ -n, x]; p[x_, n_] = ((q[x, n]/x - (x + 1)^(n - 1))/x - f[n] - f[n]*x^(n - 3))/x Table[CoefficientList[FullSimplify[ExpandAll[p[x, n]]], x], {n, 5, 10}] Flatten[%]
A347976
Triangle T(n,k) read by rows: the rows list volumes of rank 2 Schubert matroid polytopes.
Original entry on oeis.org
1, 2, 4, 3, 8, 11, 4, 13, 22, 26, 5, 19, 38, 52, 57, 6, 26, 60, 94, 114, 120, 7, 34, 89, 158, 213, 240, 247, 8, 43, 126, 251, 376, 459, 494, 502, 9, 53, 172, 381, 632, 841, 960, 1004, 1013, 10, 64, 228, 557, 1018, 1479, 1808, 1972, 2026, 2036, 11, 76, 295, 789, 1580, 2503, 3294, 3788, 4007, 4072, 4083
Offset: 3
The triangle T(n,k) starts as follows:
[n\k] [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12]
[3] 1;
[4] 2, 4;
[5] 3, 8, 11;
[6] 4, 13, 22, 26;
[7] 5, 19, 38, 52, 57;
[8] 6, 26, 60, 94, 114, 120;
[9] 7, 34, 89, 158, 213, 240, 247;
[10] 8, 43, 126, 251, 376, 459, 494, 502;
[11] 9, 53, 172, 381, 632, 841, 960, 1004, 1013;
[12] 10, 64, 228, 557, 1018, 1479, 1808, 1972, 2026, 2036;
[13] 11, 76, 295, 789, 1580, 2503, 3294, 3788, 4007, 4072, 4083;
[14] 12, 89, 374, 1088, 2374, 4089, 5804, 7090, 7804, 8089, 8166, 8178;
...
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