Original entry on oeis.org
1, 2, -3, -75, -650, -4507, -28267, -167406, -955271, -5310911, -28962586, -155616567, -826329687, -4345964510, -22675946635, -117526104883, -605643805098, -3105646720979, -15856669574339, -80653146223054
Offset: 0
-
a:=[1,2,-3,-75];; for n in [5..30] do a[n]:=10*a[n-1]-27*a[n-2]+10*a[n-3] -a[n-4]; od; a; # G. C. Greubel, Nov 25 2019
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R:=PowerSeriesRing(Integers(), 30); Coefficients(R!( (1-8*x+4*x^2-x^3)/(1-5*x+x^2)^2 )); // G. C. Greubel, Nov 25 2019
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seq(coeff(series((1-8*x+4*x^2-x^3)/(1-5*x+x^2)^2, x, n+1), x, n), n = 0..30); # G. C. Greubel, Nov 25 2019
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LinearRecurrence[{10,-27,10,-1},{1,2,-3,-75},30] (* Harvey P. Dale, Oct 29 2017 *)
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my(x='x+O('x^30)); Vec((1-8*x+4*x^2-x^3)/(1-5*x+x^2)^2) \\ G. C. Greubel, Nov 25 2019
-
def A176290_list(prec):
P. = PowerSeriesRing(ZZ, prec)
return P((1-8*x+4*x^2-x^3)/(1-5*x+x^2)^2).list()
A176290_list(30) # G. C. Greubel, Nov 25 2019
A360150
a(n) = Sum_{k=0..floor(n/3)} binomial(2*n-k,n-3*k).
Original entry on oeis.org
1, 2, 6, 21, 77, 288, 1090, 4159, 15964, 61557, 238221, 924597, 3597290, 14024341, 54770176, 214218966, 838959762, 3289471537, 12910910288, 50720828034, 199422778415, 784672001097, 3089564308849, 12172411084432, 47984843655991, 189260578353602
Offset: 0
-
A360150 := proc(n)
add(binomial(2*n-k,n-3*k),k=0..n/3) ;
end proc:
seq(A360150(n),n=0..70) ; # R. J. Mathar, Mar 12 2023
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a[n_] := Sum[Binomial[2*n - k, n - 3*k], {k, 0, Floor[n/3]}]; Array[a, 26, 0] (* Amiram Eldar, Jan 28 2023 *)
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a(n) = sum(k=0, n\3, binomial(2*n-k, n-3*k));
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my(N=30, x='x+O('x^N)); Vec(1/(sqrt(1-4*x)*(1-x^3*(2/(1+sqrt(1-4*x)))^5)))
A360152
a(n) = Sum_{k=0..floor(n/3)} binomial(2*n-5*k,n-3*k).
Original entry on oeis.org
1, 2, 6, 21, 73, 262, 960, 3562, 13347, 50393, 191406, 730555, 2799622, 10765092, 41513751, 160490906, 621805286, 2413738744, 9385635299, 36550685683, 142534105563, 556514122937, 2175296066129, 8511430278018, 33334299581686, 130662787246407
Offset: 0
-
A360152 := proc(n)
add(binomial(2*n-5*k,n-3*k),k=0..n/3) ;
end proc:
seq(A360152(n),n=0..70) ; # R. J. Mathar, Mar 12 2023
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a[n_] := Sum[Binomial[2*n - 5*k, n - 3*k], {k, 0, Floor[n/3]}]; Array[a, 26, 0] (* Amiram Eldar, Jan 28 2023 *)
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a(n) = sum(k=0, n\3, binomial(2*n-5*k, n-3*k));
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my(N=30, x='x+O('x^N)); Vec(1/(sqrt(1-4*x)*(1-2*x^3/(1+sqrt(1-4*x)))))
A360153
a(n) = Sum_{k=0..floor(n/3)} binomial(2*n-6*k,n-3*k).
Original entry on oeis.org
1, 2, 6, 21, 72, 258, 945, 3504, 13128, 49565, 188260, 718560, 2753721, 10588860, 40835160, 157871241, 611669250, 2374441380, 9233006541, 35956933050, 140220970200, 547490880981, 2140055896770, 8373651697800, 32795094564081, 128550662334522
Offset: 0
-
A360153 := proc(n)
add(binomial(2*n-6*k,n-3*k),k=0..n/3) ;
end proc:
seq(A360153(n),n=0..70) ; # R. J. Mathar, Mar 12 2023
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a[n_] := Sum[Binomial[2*n - 6*k, n - 3*k], {k, 0, Floor[n/3]}]; Array[a, 26, 0] (* Amiram Eldar, Jan 28 2023 *)
-
a(n) = sum(k=0, n\3, binomial(2*n-6*k, n-3*k));
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my(N=30, x='x+O('x^N)); Vec(1/(sqrt(1-4*x)*(1-x^3)))
A360151
a(n) = Sum_{k=0..floor(n/3)} binomial(2*n-4*k,n-3*k).
Original entry on oeis.org
1, 2, 6, 21, 74, 267, 981, 3648, 13690, 51744, 196699, 751237, 2880345, 11080081, 42743148, 165291569, 640563158, 2487083484, 9672626600, 37674470433, 146937686295, 573781535775, 2243050091905, 8777451670102, 34379401083017, 134770951530840
Offset: 0
-
A360151 := proc(n)
add(binomial(2*n-4*k,n-3*k),k=0..n/3) ;
end proc:
seq(A360151(n),n=0..70) ; # R. J. Mathar, Mar 12 2023
-
a[n_] := Sum[Binomial[2*n - 4*k, n - 3*k], {k, 0, Floor[n/3]}]; Array[a, 26, 0] (* Amiram Eldar, Jan 28 2023 *)
-
a(n) = sum(k=0, n\3, binomial(2*n-4*k, n-3*k));
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my(N=30, x='x+O('x^N)); Vec(1/(sqrt(1-4*x)*(1-x^3*(2/(1+sqrt(1-4*x)))^2)))
A307354
a(n) = Sum_{0<=i<=j<=n} (-1)^(i+j) * (i+j)!/(i!*j!).
Original entry on oeis.org
1, 2, 6, 19, 65, 231, 841, 3110, 11628, 43834, 166298, 634140, 2428336, 9331688, 35967462, 138987715, 538287881, 2088842463, 8119916647, 31613327405, 123251518641, 481125828853, 1880262896537, 7355767408395, 28803717914791, 112887697489907, 442784607413427
Offset: 0
-
Table[Sum[Sum[(-1)^(i + j)*(i + j)!/(i!*j!), {i, 0, j}], {j, 0, n}], {n, 0, 25}] (* Vaclav Kotesovec, Apr 04 2019 *)
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a(n) = sum(i=0, n, sum(j=i, n, (-1)^(i+j)*(i+j)!/(i!*j!)));
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a(n) = sum(k=0, n\3, (-1)^k*binomial(2*n-3*k, n)); \\ Seiichi Manyama, Jan 29 2023
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my(N=30, x='x+O('x^N)); Vec(1/(sqrt(1-4*x)*(1+x^3*(2/(1+sqrt(1-4*x)))^3))) \\ Seiichi Manyama, Jan 29 2023
A360168
a(n) = Sum_{k=0..floor(n/3)} binomial(2*n,n-3*k).
Original entry on oeis.org
1, 2, 6, 21, 78, 297, 1145, 4447, 17358, 68001, 267141, 1051767, 4148281, 16385111, 64797543, 256515731, 1016368078, 4030114641, 15990813773, 63485616391, 252175202373, 1002136689071, 3984080489263, 15844839393411, 63036297959993, 250855287692647
Offset: 0
-
A360168 := proc(n)
add(binomial(2*n,n-3*k),k=0..n/3) ;
end proc:
seq(A360168(n),n=0..70) ; # R. J. Mathar, Mar 12 2023
-
a[n_] := Sum[Binomial[2*n, n - 3*k], {k, 0, Floor[n/3]}]; Array[a, 26, 0] (* Amiram Eldar, Jan 28 2023 *)
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a(n) = sum(k=0, n\3, binomial(2*n, n-3*k));
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my(N=30, x='x+O('x^N)); Vec(1/(sqrt(1-4*x)*(1-x^3*(2/(1+sqrt(1-4*x)))^6)))
A371871
a(n) = Sum_{k=0..floor(n/3)} binomial(2*n-3*k-2,n-3*k).
Original entry on oeis.org
1, 0, 1, 5, 18, 66, 246, 924, 3493, 13277, 50697, 194327, 747319, 2882061, 11142027, 43167573, 167561586, 651513594, 2537041938, 9892847952, 38623197264, 150959213886, 590626854072, 2312979822738, 9065733950526, 35561306875380, 139595183125750
Offset: 0
-
A371871 := proc(n)
1/(1-x^3)/(1-x)^(n-1) ;
coeftayl(%,x=0,n) ;
end proc:
seq(A371871(n),n=0..60) ; # R. J. Mathar, Apr 22 2024
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a(n) = sum(k=0, n\3, binomial(2*n-3*k-2, n-3*k));
A371842
a(n) = Sum_{k=0..floor(n/3)} binomial(2*n-2*k+1,n-3*k).
Original entry on oeis.org
1, 3, 10, 36, 133, 498, 1882, 7161, 27391, 105210, 405499, 1567332, 6072724, 23578221, 91712089, 357301827, 1393986898, 5445422340, 21296030401, 83370591273, 326688422203, 1281227165640, 5028742763407, 19751799462378, 77632592859316, 305316702610581
Offset: 0
A371854
a(n) = Sum_{k=0..floor(n/3)} binomial(2*n-k+2,n-3*k).
Original entry on oeis.org
1, 4, 15, 57, 219, 847, 3290, 12819, 50066, 195909, 767790, 3013002, 11837043, 46548919, 183209125, 721628692, 2844297119, 11217639757, 44265835891, 174765349896, 690308413773, 2727823240762, 10783518961394, 42644560775835, 168699835910561, 667580653569309
Offset: 0
Showing 1-10 of 10 results.