A236770
a(n) = n*(n + 1)*(3*n^2 + 3*n - 2)/8.
Original entry on oeis.org
0, 1, 12, 51, 145, 330, 651, 1162, 1926, 3015, 4510, 6501, 9087, 12376, 16485, 21540, 27676, 35037, 43776, 54055, 66045, 79926, 95887, 114126, 134850, 158275, 184626, 214137, 247051, 283620, 324105, 368776, 417912, 471801, 530740, 595035, 665001, 740962
Offset: 0
-
[n*(n+1)*(3*n^2+3*n-2)/8: n in [0..40]];
-
Table[n (n + 1) (3 n^2 + 3 n - 2)/8, {n, 0, 40}]
LinearRecurrence[{5,-10,10,-5,1},{0,1,12,51,145},40] (* Harvey P. Dale, Aug 22 2016 *)
-
for(n=0, 40, print1(n*(n+1)*(3*n^2+3*n-2)/8", "));
A085461
Number of 5-tuples (v1,v2,v3,v4,v5) of nonnegative integers less than n such that v1 <= v5, v2 <= v5, v2 <= v4 and v3 <= v4.
Original entry on oeis.org
1, 13, 70, 246, 671, 1547, 3164, 5916, 10317, 17017, 26818, 40690, 59787, 85463, 119288, 163064, 218841, 288933, 375934, 482734, 612535, 768867, 955604, 1176980, 1437605, 1742481, 2097018, 2507050, 2978851, 3519151, 4135152, 4834544
Offset: 1
- S. J. Cyvin and I. Gutman, Kekulé structures in benzenoid hydrocarbons, Lecture Notes in Chemistry, No. 46, Springer, New York, 1988 (p. 168).
- G. C. Greubel, Table of n, a(n) for n = 1..1000
- Goran Kilibarda and Vladeta Jovovic, Antichains of Multisets, J. Integer Seqs., Vol. 7, 2004.
- Daeseok Lee and H.-K. Ju, An Extension of Hibi's palindromic theorem, arXiv preprint arXiv:1503.05658 [math.CO], 2015.
- R. P. Stanley, Examples of Magic Labelings, Unpublished Notes, 1973 [Cached copy, with permission]
- See p. 31
- Index entries for linear recurrences with constant coefficients, signature (6,-15,20,-15,6,-1).
-
Rest[CoefficientList[Series[x*(1 + x)*(1 + 6*x + x^2)/(1 - x)^6, {x, 0, 50}], x]] (* G. C. Greubel, Oct 06 2017 *)
-
x='x+O('x^50); Vec(x*(1+x)*(1+6*x+x^2)/(1-x)^6) \\ G. C. Greubel, Oct 06 2017
A085465
Number of monotone n-weightings of complete bipartite digraph K(3,3).
Original entry on oeis.org
1, 15, 102, 442, 1443, 3885, 9100, 19188, 37269, 67771, 116754, 192270, 304759, 467481, 696984, 1013608, 1442025, 2011815, 2758078, 3722082, 4951947, 6503365, 8440356, 10836060, 13773565, 17346771, 21661290, 26835382, 33000927, 40304433
Offset: 1
- G. C. Greubel, Table of n, a(n) for n = 1..1000
- Goran Kilibarda and Vladeta Jovovic, Antichains of Multisets, J. Integer Seqs., Vol. 7, 2004.
- H. Mühle, Counting Proper Mergings of Chains and Antichains, arXiv:1206.3922 [math.CO], 2012.
- Index entries for linear recurrences with constant coefficients, signature (7,-21,35,-35,21,-7,1).
-
[1/20*n*(n+1)*(n^2+1)*(n^2+2*n+2): n in [1..40]]; // Vincenzo Librandi, Oct 06 2017
-
Rest[CoefficientList[Series[x*(1 + 4*x + x^2)^2/(1 - x)^7, {x, 0, 50}], x]] (* G. C. Greubel, Oct 06 2017 *)
LinearRecurrence[{7, -21, 35, -35, 21, -7, 1}, {1, 15, 102, 442, 1443, 3885, 9100}, 40] (* Vincenzo Librandi, Oct 06 2017 *)
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x='x+O('x^50); Vec(x*(1+4*x+x^2)^2/(1-x)^7) \\ G. C. Greubel, Oct 06 2017
A085462
Number of 5-tuples (v1,v2,v3,v4,v5) of nonnegative integers less than n such that v1<=v4, v1<=v5, v2<=v4 and v3<=v4.
Original entry on oeis.org
1, 14, 77, 273, 748, 1729, 3542, 6630, 11571, 19096, 30107, 45695, 67158, 96019, 134044, 183260, 245973, 324786, 422617, 542717, 688688, 864501, 1074514, 1323490, 1616615, 1959516, 2358279, 2819467, 3350138, 3957863, 4650744
Offset: 1
- G. C. Greubel, Table of n, a(n) for n = 1..1000
- Goran Kilibarda and Vladeta Jovovic, Antichains of Multisets, J. Integer Seqs., Vol. 7, 2004.
- J. M. Landsberg and L. Manivel, The sextonions and E7 1/2, Adv. Math. 201 (2006), 143-179. [Th. 7.1, case a=-2/3]
- Index entries for linear recurrences with constant coefficients, signature (6,-15,20,-15,6,-1).
-
[n*(n+1)*(2*n+1)*(3*n+1)*(3*n+2)/120: n in [0..50]]; // G. C. Greubel, Oct 07 2017
-
Rest[CoefficientList[Series[x*(1 + x)*(1 + 7*x + x^2)/(1 - x)^6, {x, 0, 50}], x]] (* or *) Table[n*(n+1)*(2*n+1)*(3*n+1)*(3*n+2)/120, {n,0,50}] (* G. C. Greubel, Oct 07 2017 *)
-
x='x+O('x^50); Vec(x*(1+x)*(1+7*x+x^2)/(1-x)^6) \\ G. C. Greubel, Oct 07 2017
A085463
Number of 5-tuples (v1,v2,v3,v4,v5) of nonnegative integers less than n such that v1<=v4, v1<=v5, v2<=v4, v2<=v5 and v3<=v4.
Original entry on oeis.org
1, 12, 63, 219, 594, 1365, 2786, 5202, 9063, 14938, 23529, 35685, 52416, 74907, 104532, 142868, 191709, 253080, 329251, 422751, 536382, 673233, 836694, 1030470, 1258595, 1525446, 1835757, 2194633, 2607564, 3080439, 3619560, 4231656
Offset: 1
- G. C. Greubel, Table of n, a(n) for n = 1..1000
- Goran Kilibarda and Vladeta Jovovic, Antichains of Multisets, J. Integer Seqs., Vol. 7, 2004.
- Index entries for linear recurrences with constant coefficients, signature (6,-15,20,-15,6,-1).
-
[n*(n+1)*(2*n+1)*(7*n^2 + 7*n + 6)/120: n in [1..25]]; // G. C. Greubel, Oct 07 2017
-
Table[n*(n+1)*(2*n+1)*(7*n^2 + 7*n + 6)/120, {n,1,25}] (* G. C. Greubel, Oct 07 2017 *)
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for(n=1,25, print1(n*(n+1)*(2*n+1)*(7*n^2 + 7*n + 6)/120, ", ")) \\ G. C. Greubel, Oct 07 2017
A085464
Number of monotone n-weightings of complete bipartite digraph K(4,2).
Original entry on oeis.org
1, 19, 134, 586, 1919, 5173, 12124, 25572, 49677, 90343, 155650, 256334, 406315, 623273, 929272, 1351432, 1922649, 2682363, 3677374, 4962706, 6602519, 8671069, 11253716, 14447980, 18364645, 23128911, 28881594, 35780374, 44001091
Offset: 1
-
[(1/30)*n*(n+1)*(2*n^4+4*n^3+6*n^2+4*n-1): n in [1..25]]; // G. C. Greubel, Oct 07 2017
-
Table[(1/30)*n*(n+1)*(2*n^4+4*n^3+6*n^2+4*n-1), {n,1,50}] (* G. C. Greubel, Oct 07 2017 *)
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a(n)=n*(n+1)*(2*n^4+4*n^3+6*n^2+4*n-1)/30 \\ Charles R Greathouse IV, Jan 16 2013
A264854
a(n) = n*(n + 1)*(11*n^2 + 11*n - 10)/24.
Original entry on oeis.org
0, 1, 14, 61, 175, 400, 791, 1414, 2346, 3675, 5500, 7931, 11089, 15106, 20125, 26300, 33796, 42789, 53466, 66025, 80675, 97636, 117139, 139426, 164750, 193375, 225576, 261639, 301861, 346550, 396025, 450616, 510664, 576521, 648550, 727125, 812631, 905464, 1006031
Offset: 0
Cf. similar sequences provided by the partial sums of centered k-gonal pyramidal numbers:
A006522 (k=1),
A006007 (k=2),
A002817 (k=3),
A006325 (k=4),
A006322 (k=5),
A000537 (k=6),
A006323 (k=7),
A006324 (k=8),
A236770 (k=9),
A264853 (k=10), this sequence (k=11),
A062392 (k=12),
A264888 (k=13).
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[n*(n+1)*(11*n^2+11*n-10)/24: n in [0..50]]; // Vincenzo Librandi, Nov 27 2015
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Table[n (n + 1) (11 n^2 + 11 n - 10)/24, {n, 0, 50}]
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a(n)=n*(n+1)*(11*n^2+11*n-10)/24 \\ Charles R Greathouse IV, Jul 26 2016
A362863
Centered hecatonicosachoral numbers.
Original entry on oeis.org
1, 1441, 11521, 44641, 122401, 273601, 534241, 947521, 1563841, 2440801, 3643201, 5243041, 7319521, 9959041, 13255201, 17308801, 22227841, 28127521, 35130241, 43365601, 52970401, 64088641, 76871521, 91477441, 108072001, 126828001, 147925441, 171551521, 197900641
Offset: 1
A071910
a(n) = t(n)*t(n+1)*t(n+2), where t() are the triangular numbers.
Original entry on oeis.org
0, 18, 180, 900, 3150, 8820, 21168, 45360, 89100, 163350, 283140, 468468, 745290, 1146600, 1713600, 2496960, 3558168, 4970970, 6822900, 9216900, 12273030, 16130268, 20948400, 26910000, 34222500, 43120350, 53867268, 66758580, 82123650, 100328400, 121777920
Offset: 0
Cf.
A006542, (first differences of a(n) /18)
A006414, (second differences of a(n) /18)
A006322, (third differences of a(n) /18)
A004068, (fourth differences of a(n) /18)
A005891, (fifth differences of a(n) /18)
A008706.
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Join[{0},Times@@@Partition[Accumulate[Range[40]],3,1]] (* or *) LinearRecurrence[{7,-21,35,-35,21,-7,1},{0,18,180,900,3150,8820,21168},40] (* Harvey P. Dale, Aug 08 2025 *)
-
t(n) = n*(n+1)/2;
a(n) = t(n)*t(n+1)*t(n+2); \\ Michel Marcus, Oct 21 2015
A373424
Array read by ascending antidiagonals: T(n, k) = [x^k] cf(n) where cf(n) is the continued fraction (-1)^n/(~x - 1/(~x - ... 1/(~x - 1)))...) and where '~' is '-' if n is even, and '+' if n is odd, and x appears n times in the expression.
Original entry on oeis.org
1, 1, 0, 1, 1, 0, 1, 2, 1, 0, 1, 3, 3, 1, 0, 1, 4, 6, 5, 1, 0, 1, 5, 10, 14, 8, 1, 0, 1, 6, 15, 30, 31, 13, 1, 0, 1, 7, 21, 55, 85, 70, 21, 1, 0, 1, 8, 28, 91, 190, 246, 157, 34, 1, 0, 1, 9, 36, 140, 371, 671, 707, 353, 55, 1, 0, 1, 10, 45, 204, 658, 1547, 2353, 2037, 793, 89, 1, 0
Offset: 0
Generating functions of the rows:
gf0 = 1;
gf1 = -1/( x-1);
gf2 = 1/(-x-1/(-x-1));
gf3 = -1/( x-1/( x-1/( x-1)));
gf4 = 1/(-x-1/(-x-1/(-x-1/(-x-1))));
gf5 = -1/( x-1/( x-1/( x-1/( x-1/( x-1)))));
gf6 = 1/(-x-1/(-x-1/(-x-1/(-x-1/(-x-1/(-x-1))))));
...
Array A(n, k) starts:
[0] 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, ... A000007
[1] 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, ... A000012
[2] 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ... A000045
[3] 1, 3, 6, 14, 31, 70, 157, 353, 793, 1782, ... A006356
[4] 1, 4, 10, 30, 85, 246, 707, 2037, 5864, 16886, ... A006357
[5] 1, 5, 15, 55, 190, 671, 2353, 8272, 29056, 102091, ... A006358
[6] 1, 6, 21, 91, 371, 1547, 6405, 26585, 110254, 457379, ... A006359
A000027,A000330, A085461, A244881, ...
A000217, A006322, A108675, ...
.
Triangle T(n, k) = A(n - k, k) starts:
[0] 1;
[1] 1, 0;
[2] 1, 1, 0;
[3] 1, 2, 1, 0;
[4] 1, 3, 3, 1, 0;
[5] 1, 4, 6, 5, 1, 0;
[6] 1, 5, 10, 14, 8, 1, 0;
-
row := proc(n, len) local x, a, j, ser; if irem(n, 2) = 1 then
a := x - 1; for j from 1 to n do a := x - 1 / a od: a := a - x; else
a := -x - 1; for j from 1 to n do a := -x - 1 / a od: a := -a - x;
fi; ser := series(a, x, len + 2); seq(coeff(ser, x, j), j = 0..len) end:
A := (n, k) -> row(n, 12)[k+1]: # array form
T := (n, k) -> row(n - k, k+1)[k+1]: # triangular form
-
def Arow(n, len):
R. = PowerSeriesRing(ZZ, len)
if n == 0: return [1] + [0]*(len - 1)
x = -x if n % 2 else x
a = x + 1
for _ in range(n):
a = x - 1 / a
a = x - a if n % 2 else a - x
return a.list()
for n in range(7): print(Arow(n, 10))
Comments