A211422 Number of ordered triples (w,x,y) with all terms in {-n,...,0,...,n} and w^2 + x*y = 0.
1, 9, 17, 25, 41, 49, 57, 65, 81, 105, 113, 121, 137, 145, 153, 161, 193, 201, 225, 233, 249, 257, 265, 273, 289, 329, 337, 361, 377, 385, 393, 401, 433, 441, 449, 457, 505, 513, 521, 529, 545, 553, 561, 569, 585, 609, 617, 625, 657, 713, 753, 761
Offset: 0
Keywords
A182260
Number of ordered triples (w,x,y) with all terms in {1,...,n} and 2w
0, 3, 11, 28, 56, 99, 159, 240, 344, 475, 635, 828, 1056, 1323, 1631, 1984, 2384, 2835, 3339, 3900, 4520, 5203, 5951, 6768, 7656, 8619, 9659, 10780, 11984, 13275, 14655, 16128, 17696, 19363, 21131, 23004, 24984, 27075, 29279, 31600, 34040
Offset: 1
Comments
Examples
For n=2, the 3 triples (w,x,y) for which 2w<x+y are (1,1,2), (1,2,1), (1,2,2). The 3 triples for which 2w>x+y are (2,1,1), (2,1,2), (2,2,1).
Links
- Index entries for linear recurrences with constant coefficients, signature (3,-2,-2,3,-1).
Programs
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Mathematica
(See the program at A211802.) LinearRecurrence[{3,-2,-2,3,-1},{0,3,11,28,56},50] (* Harvey P. Dale, Aug 10 2019 *)
Formula
a(n) = 3*a(n-1)-2*a(n-2)-2*a(n-3)+3*a(n-4)-a(n-5).
From Colin Barker, May 06 2012: (Start)
a(n) = (-1+(-1)^n-2*n^2+4*n^3)/8.
G.f.: x^2*(3 + 2*x + x^2)/((1 - x)^4*(1 + x)). (End)
A182259
Rectangular array: R(k,n) = number of ordered triples (w,x,y) with all terms in {1,...,n} and 2w^k<=x^k+y
0, 3, 0, 11, 3, 0, 28, 11, 3, 0, 56, 28, 11, 3, 0, 99, 56, 26, 11, 3, 0, 159, 97, 52, 26, 11, 3, 0, 240, 153, 93, 50, 26, 11, 3, 0, 344, 230, 149, 85, 50, 26, 11, 3, 0, 475, 330, 222, 139, 85, 50, 26, 11, 3, 0, 635, 453, 314, 212, 133, 85, 50, 26, 11, 3, 0, 828
Offset: 1
Comments
Examples
Northwest corner (with antidiagonals read from northeast to southwest): 0...3...11...28...56...99...159 0...3...11...28...56...97...153 0...3...11...26...52...93...149 0...3...11...26...50...85...139 0...3...11...26...50...85...133
Crossrefs
Cf. A211790.
Programs
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Mathematica
z = 48; t[k_, n_] := Module[{s = 0}, (Do[If[2 w^k > x^k + y^k, s = s + 1], {w, 1, #}, {x, 1, #}, {y, 1, #}] &[n]; s)]; Table[t[1, n], {n, 1, z}] (* A182260 *) Table[t[2, n], {n, 1, z}] (* A211810 *) Table[t[3, n], {n, 1, z}] (* A211811 *) TableForm[Table[t[k, n], {k, 1, 12}, {n, 1, 16}]] Flatten[Table[t[k, n - k + 1], {n, 1, 12}, {k, 1, n}]] (* A182259 *) Table[k (k - 1) (2 k + 5)/6, {k, 1, z}] (* row-limit sequence, A051925 *) (* Peter J. C. Moses, Apr 13 2012 *)
A211802 R(k,n) = number of ordered triples (w,x,y) with all terms in {1,...,n} and 2*w^k < x^k + y^k; square array read by descending antidiagonals.
0, 3, 0, 11, 3, 0, 28, 13, 3, 0, 56, 32, 13, 3, 0, 99, 64, 34, 13, 3, 0, 159, 113, 68, 34, 13, 3, 0, 240, 181, 117, 70, 34, 13, 3, 0, 344, 272, 187, 125, 70, 34, 13, 3, 0, 475, 388, 282, 197, 125, 70, 34, 13, 3, 0, 635, 535, 406, 292, 203, 125, 70, 34, 13, 3, 0
Offset: 1
Comments
Examples
Northwest corner: 0 3 11 28 56 99 159 240 0 3 13 32 64 113 181 272 0 3 13 34 68 117 187 282 0 3 13 34 70 125 197 292 0 3 13 34 70 125 203 302
Programs
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Mathematica
z = 48; t[k_, n_] := Module[{s = 0}, (Do[If[2 w^k < x^k + y^k, s = s + 1], {w, 1, #}, {x, 1, #}, {y, 1, #}] &[n]; s)]; Table[t[1, n], {n, 1, z}] (* A182260 *) Table[t[2, n], {n, 1, z}] (* A211800 *) Table[t[3, n], {n, 1, z}] (* A211801 *) TableForm[Table[t[k, n], {k, 1, 12}, {n, 1, 16}]] Flatten[Table[t[k, n - k + 1], {n, 1, 12}, {k, 1, n}]] (* this sequence *) Table[k (k - 1) (4 k + 1)/6, {k, 1, z}] (* row-limit sequence, A016061 *) (* Peter J. C. Moses, Apr 13 2012 *)
Extensions
Definition corrected by Georg Fischer, Sep 10 2022
A211805
Rectangular array: R(k,n) = number of ordered triples (w,x,y) with all terms in {1,...,n} and 2w^k>=x^k+y
1, 5, 1, 16, 5, 1, 36, 14, 5, 1, 69, 32, 14, 5, 1, 117, 61, 30, 14, 5, 1, 184, 103, 57, 30, 14, 5, 1, 272, 162, 99, 55, 30, 14, 5, 1, 385, 240, 156, 91, 55, 30, 14, 5, 1, 525, 341, 230, 146, 91, 55, 30, 14, 5, 1, 696, 465, 323, 220, 140, 91, 55, 30, 14, 5, 1, 900
Offset: 1
Comments
Examples
Northwest corner: 1...5...16...36...69...117...184 1...5...14...32...61...103...162 1...5...14...30...57...99....156 1...5...14...30...55...91....146 1...5...14...30...55...91....140
Crossrefs
Cf. A211790.
Programs
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Mathematica
z = 48; t[k_, n_] := Module[{s = 0}, (Do[If[2 w^k >= x^k + y^k, s = s + 1], {w, 1, #}, {x, 1, #}, {y, 1, #}] &[n]; s)]; Table[t[1, n], {n, 1, z}] (* A055232 *) Table[t[2, n], {n, 1, z}] (* A211803 *) Table[t[3, n], {n, 1, z}] (* A211804 *) TableForm[Table[t[k, n], {k, 1, 12}, {n, 1, 16}]] Flatten[Table[t[k, n - k + 1], {n, 1, 12}, {k, 1, n}]] (* A211805 *) Table[k (k + 1) (2 k + 1)/6, {k, 1, z}] (* row-limit sequence, A000330 *) (* Peter J. C. Moses, Apr 13 2012 *)
A211808
Rectangular array: R(k,n) = number of ordered triples (w,x,y) with all terms in {1,...,n} and 2w^k<=x^k+y
1, 5, 1, 16, 5, 1, 36, 16, 5, 1, 69, 36, 16, 5, 1, 117, 69, 38, 16, 5, 1, 184, 119, 73, 38, 16, 5, 1, 272, 190, 123, 75, 38, 16, 5, 1, 385, 282, 194, 131, 75, 38, 16, 5, 1, 525, 399, 290, 204, 131, 75, 38, 16, 5, 1, 696, 547, 415, 300, 210, 131, 75, 38, 16, 5, 1
Offset: 1
Comments
Examples
Northwest corner: 1...5...16...36...69...117...184 1...5...16...36...69...119...190 1...5...16...38...73...123...194 1...5...16...38...75...131...204 1...5...16...38...75...131...210
Crossrefs
Cf. A211790.
Programs
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Mathematica
z = 48; t[k_, n_] := Module[{s = 0}, (Do[If[2 w^k <= x^k + y^k, s = s + 1], {w, 1, #}, {x, 1, #}, {y, 1, #}] &[n]; s)]; Table[t[1, n], {n, 1, z}] (* A055232 *) Table[t[2, n], {n, 1, z}] (* A211806 *) Table[t[3, n], {n, 1, z}] (* A211807 *) TableForm[Table[t[k, n], {k, 1, 12}, {n, 1, 16}]] Flatten[Table[t[k, n - k + 1], {n, 1, 12}, {k, 1, n}]] (* A211808 *) Table[k (4 k^2 - 3 k + 5)/6, {k, 1, z}] (* row-limit sequence, A174723 *) (* Peter J. C. Moses, Apr 13 2012 *)
A211796 Rectangular array: R(k,n) = number of ordered triples (w,x,y) with all terms in {1,...,n} and w^k<=x^k+y^k.
1, 8, 1, 26, 7, 1, 60, 22, 7, 1, 115, 51, 22, 7, 1, 196, 99, 50, 22, 7, 1, 308, 168, 96, 50, 22, 7, 1, 456, 265, 163, 95, 50, 22, 7, 1, 645, 393, 255, 161, 95, 50, 22, 7, 1, 880, 556, 378, 253, 161, 95, 50, 22, 7, 1, 1166, 760, 534, 374, 252, 161, 95, 50, 22, 7
Offset: 1
Comments
Examples
Northwest corner: 1...8...26...60...115...196...308 1...7...22...51...99....168...265 1...7...22...50...96....163...255 1...7...22...50...95....161...253 1...7...22...50...95....161...252
Crossrefs
Cf. A211790.
Programs
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Mathematica
z = 48; t[k_, n_] := Module[{s = 0}, (Do[If[w^k <= x^k + y^k, s = s + 1], {w, 1, #}, {x, 1, #}, {y, 1, #}] &[n]; s)]; Table[t[1, n], {n, 1, z}] (* A002413 *) Table[t[2, n], {n, 1, z}] (* A211634 *) Table[t[3, n], {n, 1, z}] (* A211650 *) TableForm[Table[t[k, n], {k, 1, 12}, {n, 1, 16}]] Flatten[Table[t[k, n - k + 1], {n, 1, 12}, {k, 1, n}]] (* A211796 *) Table[k (k - 1) (2 k - 1)/6, {k, 1, z}] (* row-limit sequence, A002412 *) (* Peter J. C. Moses, Apr 13 2012 *)
A211799
Rectangular array: R(k,n) = number of ordered triples (w,x,y) with all terms in {1,...,n} and w^k<=x^k+y
0, 0, 0, 1, 1, 0, 4, 5, 1, 0, 10, 13, 5, 1, 0, 20, 26, 14, 5, 1, 0, 35, 48, 29, 14, 5, 1, 0, 56, 78, 53, 30, 14, 5, 1, 0, 84, 119, 88, 55, 30, 14, 5, 1, 0, 120, 173, 134, 90, 55, 30, 14, 5, 1, 0, 165, 240, 195, 138, 91, 55, 30, 14, 5, 1, 0, 220, 323, 270, 201, 139, 91
Offset: 1
Comments
Examples
Northwest corner: 0...0...1...4....10...20...35...56 0...1...5...13...26...48...78...119 0...1...5...14...29...53...88...134 0...1...5...14...30...55...90...138 0...1...5...14...30...55...91...139
Crossrefs
Cf. A211790.
Programs
-
Mathematica
z = 48; t[k_, n_] := Module[{s = 0}, (Do[If[w^k > x^k + y^k, s = s + 1], {w, 1, #}, {x, 1, #}, {y, 1, #}] &[n]; s)]; Table[t[1, n], {n, 1, z}] (* A000292 *) Table[t[2, n], {n, 1, z}] (* A211637 *) Table[t[3, n], {n, 1, z}] (* A211651 *) TableForm[Table[t[k, n], {k, 1, 12}, {n, 1, 16}]] Flatten[Table[t[k, n - k + 1], {n, 1, 12}, {k, 1, n}]] (* A211799 *) Table[k (k - 1) (2 k - 1)/6, {k, 1, z}] (* row-limit sequence, A000330 *) (* Peter J. C. Moses, Apr 13 2012 *)
A211801
Number of ordered triples (w,x,y) with all terms in {1,...,n} and 2w^3
0, 3, 13, 34, 68, 117, 187, 282, 406, 559, 743, 966, 1232, 1545, 1899, 2304, 2764, 3285, 3869, 4512, 5222, 6005, 6867, 7812, 8828, 9931, 11125, 12412, 13798, 15271, 16847, 18532, 20330, 22239, 24255, 26394, 28660, 31055, 33573, 36222
Offset: 1
Keywords
Programs
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Mathematica
(See the program at A211802.)
A211807 Number of ordered triples (w,x,y) with all terms in {1,...,n} and 2w^3<=x^3+y^3.
1, 5, 16, 38, 73, 123, 194, 290, 415, 569, 754, 978, 1245, 1559, 1914, 2320, 2781, 3303, 3888, 4532, 5243, 6027, 6890, 7836, 8853, 9957, 11152, 12440, 13827, 15301, 16878, 18564, 20363, 22273, 24290, 26430, 28697, 31093, 33612, 36262
Offset: 1
Keywords
Links
- Robert Israel, Table of n, a(n) for n = 1..10000
Programs
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Maple
f:= proc(n) local x; n + add(2*floor(((x^3+n^3)/2)^(1/3)), x=1..n-1) end proc: ListTools:-PartialSums(map(f,[$1..50])); # Robert Israel, Jan 26 2025
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Mathematica
(See the program at A211808.)
Comments
Examples
Links
Crossrefs
Programs
Mathematica