A245334
A factorial-like triangle read by rows: T(0,0) = 1; T(n+1,0) = T(n,0)+1; T(n+1,k+1) = T(n,0)*T(n,k), k=0..n.
Original entry on oeis.org
1, 2, 1, 3, 4, 2, 4, 9, 12, 6, 5, 16, 36, 48, 24, 6, 25, 80, 180, 240, 120, 7, 36, 150, 480, 1080, 1440, 720, 8, 49, 252, 1050, 3360, 7560, 10080, 5040, 9, 64, 392, 2016, 8400, 26880, 60480, 80640, 40320, 10, 81, 576, 3528, 18144, 75600, 241920, 544320
Offset: 0
. 0: 1;
. 1: 2, 1;
. 2: 3, 4, 2;
. 3: 4, 9, 12, 6;
. 4: 5, 16, 36, 48, 24;
. 5: 6, 25, 80, 180, 240, 120;
. 6: 7, 36, 150, 480, 1080, 1440, 720;
. 7: 8, 49, 252, 1050, 3360, 7560, 10080, 5040;
. 8: 9, 64, 392, 2016, 8400, 26880, 60480, 80640, 40320;
. 9: 10, 81, 576, 3528, 18144, 75600, 241920, 544320, 725760, 362880.
Cf.
A000142,
A001715,
A001720,
A001725,
A001730,
A049388,
A049389,
A049398,
A051431,
A052849,
A070960.
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a245334 n k = a245334_tabl !! n !! k
a245334_row n = a245334_tabl !! n
a245334_tabl = iterate (\row@(h:_) -> (h + 1) : map (* h) row) [1]
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Table[(n!)/((n - k)!)*(n + 1 - k), {n, 0, 9}, {k, 0, n}] // Flatten (* Michael De Vlieger, Sep 10 2017 *)
A030297
a(n) = n*(n + a(n-1)) with a(0)=0.
Original entry on oeis.org
0, 1, 6, 27, 124, 645, 3906, 27391, 219192, 1972809, 19728190, 217010211, 2604122676, 33853594957, 473950329594, 7109254944135, 113748079106416, 1933717344809361, 34806912206568822, 661331331924807979
Offset: 0
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f := proc(n) options remember; if n <= 1 then n elif n = 2 then 6 else -n*(n-2)*f(n-3)+(n-3)*n*f(n-2)+3*n*f(n-1)/(n-1); fi; end;
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a=0;lst={a};Do[a=(a+n)*n;AppendTo[lst, a], {n, 2*4!}];lst (* Vladimir Joseph Stephan Orlovsky, Dec 14 2008 *)
RecurrenceTable[{a[0]==0,a[n]==n(n+a[n-1])},a[n],{n,20}] (* Harvey P. Dale, Oct 22 2011 *)
Round@Table[(2 E Gamma[n, 1] - 1) n, {n, 0, 20}] (* Round is equivalent to FullSimplify here, but is much faster - Vladimir Reshetnikov, Oct 07 2016 *)
A285201
Stage at which Ken Knowlton's elevator (version 1) reaches floor n for the first time.
Original entry on oeis.org
1, 2, 5, 14, 45, 174, 825, 4738, 32137, 251338, 2224157, 21952358, 238962581, 2843085270, 36696680241, 510647009850, 7619901954001, 121367981060434, 2055085325869813, 36861997532438654, 698193329457246653, 13924819967953406654, 291683979376372766697, 6402385486361598687666, 146948520147021794869977
Offset: 1
R. L. Graham, May 02 2017
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a:= proc(n) option remember; `if`(n<3, n, ((n-1)^2*a(n-1)
-(n-2)*(2*n-3)*a(n-2)+(n-1)*(n-3)*a(n-3))/(n-2))
end:
seq(a(n), n=1..25); # Alois P. Heinz, Jul 11 2018
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a[n_] := 2 - n + 2 Sum[k!/j!, {k, 0, n-2}, {j, 0, k}];
Array[a, 25] (* Jean-François Alcover, Nov 01 2020 *)
A240993
A000142 (n+1) * A002109(n), a product of factorials and hyperfactorials.
Original entry on oeis.org
1, 2, 24, 2592, 3317760, 62208000000, 20316635136000000, 133852981198454784000000, 20211123400293732996612096000000, 78302033109811407811828935756349440000000, 8613223642079254859301182933198438400000000000000000
Offset: 0
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a240993 n = a000142 (n + 1) * a002109 n
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Table[(n+1)!*Hyperfactorial[n], {n, 0, 10}] (* Vaclav Kotesovec, Nov 14 2014 *)
Table[(n+1)*(n!)^(n+1)/BarnesG[n+1], {n, 0, 10}] (* Vaclav Kotesovec, Nov 14 2014 *)
A347667
Triangle read by rows: T(n,k) = Sum_{j=0..k} binomial(n,j) * j! (0 <= k <= n).
Original entry on oeis.org
1, 1, 2, 1, 3, 5, 1, 4, 10, 16, 1, 5, 17, 41, 65, 1, 6, 26, 86, 206, 326, 1, 7, 37, 157, 517, 1237, 1957, 1, 8, 50, 260, 1100, 3620, 8660, 13700, 1, 9, 65, 401, 2081, 8801, 28961, 69281, 109601, 1, 10, 82, 586, 3610, 18730, 79210, 260650, 623530, 986410
Offset: 0
Triangle begins:
1;
1, 2;
1, 3, 5;
1, 4, 10, 16;
1, 5, 17, 41, 65;
1, 6, 26, 86, 206, 326;
1, 7, 37, 157, 517, 1237, 1957;
1, 8, 50, 260, 1100, 3620, 8660, 13700;
...
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T[n_, k_] := Sum[Binomial[n, j] j!, {j, 0, k}]; Table[T[n, k], {n, 0, 9}, {k, 0, n}] // Flatten
Showing 1-5 of 5 results.
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