A213500
Rectangular array T(n,k): (row n) = b**c, where b(h) = h, c(h) = h + n - 1, n >= 1, h >= 1, and ** = convolution.
Original entry on oeis.org
1, 4, 2, 10, 7, 3, 20, 16, 10, 4, 35, 30, 22, 13, 5, 56, 50, 40, 28, 16, 6, 84, 77, 65, 50, 34, 19, 7, 120, 112, 98, 80, 60, 40, 22, 8, 165, 156, 140, 119, 95, 70, 46, 25, 9, 220, 210, 192, 168, 140, 110, 80, 52, 28, 10, 286, 275, 255, 228, 196, 161, 125, 90
Offset: 1
Northwest corner (the array is read by southwest falling antidiagonals):
1, 4, 10, 20, 35, 56, 84, ...
2, 7, 16, 30, 50, 77, 112, ...
3, 10, 22, 40, 65, 98, 140, ...
4, 13, 28, 50, 80, 119, 168, ...
5, 16, 34, 60, 95, 140, 196, ...
6, 19, 40, 70, 110, 161, 224, ...
T(6,1) = (1)**(6) = 6;
T(6,2) = (1,2)**(6,7) = 1*7+2*6 = 19;
T(6,3) = (1,2,3)**(6,7,8) = 1*8+2*7+3*6 = 40.
-
b[n_] := n; c[n_] := n
t[n_, k_] := Sum[b[k - i] c[n + i], {i, 0, k - 1}]
TableForm[Table[t[n, k], {n, 1, 10}, {k, 1, 10}]]
Flatten[Table[t[n - k + 1, k], {n, 12}, {k, n, 1, -1}]]
r[n_] := Table[t[n, k], {k, 1, 60}] (* A213500 *)
-
t(n,k) = sum(i=0, k - 1, (k - i) * (n + i));
tabl(nn) = {for(n=1, nn, for(k=1, n, print1(t(k,n - k + 1),", ");); print(););};
tabl(12) \\ Indranil Ghosh, Mar 26 2017
-
def t(n, k): return sum((k - i) * (n + i) for i in range(k))
for n in range(1, 13):
print([t(k, n - k + 1) for k in range(1, n + 1)]) # Indranil Ghosh, Mar 26 2017
A143328
Table T(n,k) read by antidiagonals. T(n,k) is the number of primitive (=aperiodic) k-ary Lyndon words (n,k >= 1) with length less than or equal to n.
Original entry on oeis.org
1, 2, 1, 3, 3, 1, 4, 6, 5, 1, 5, 10, 14, 8, 1, 6, 15, 30, 32, 14, 1, 7, 21, 55, 90, 80, 23, 1, 8, 28, 91, 205, 294, 196, 41, 1, 9, 36, 140, 406, 829, 964, 508, 71, 1, 10, 45, 204, 728, 1960, 3409, 3304, 1318, 127, 1, 11, 55, 285, 1212, 4088, 9695, 14569, 11464, 3502, 226, 1
Offset: 1
T(3,2) = 5, because 5 words of length <=3 over 2-letter alphabet {a,b} are primitive Lyndon words: a, b, ab, aab, abb.
Table begins:
1, 2, 3, 4, 5, ...
1, 3, 6, 10, 15, ...
1, 5, 14, 30, 55, ...
1, 8, 32, 90, 205, ...
1, 14, 80, 294, 829, ...
-
with(numtheory):
f0:= proc(n) option remember; unapply(k^n-add(f0(d)(k),
d=divisors(n)minus{n}), k)
end:
f2:= proc(n) option remember; unapply(f0(n)(x)/n, x) end:
g2:= proc(n) option remember; unapply(add(f2(j)(x), j=1..n), x) end:
T:= (n,k)-> g2(n)(k):
seq(seq(T(n, 1+d-n), n=1..d), d=1..12);
-
f0[n_] := f0[n] = Function[k, k^n-Sum[f0[d][k], {d, Divisors[n]//Most}]]; f2[n_] := f2[n] = Function[x, f0[n][x]/n]; g2[n_] := g2[n] = Function[x, Sum[f2[j][x], {j, 1, n}]]; T[n_, k_] := g2[n][k]; Table[T[n, 1+d-n], {d, 1, 12}, {n, 1, d}]//Flatten (* Jean-François Alcover, Feb 12 2014, translated from Maple *)
A213771
Rectangular array: (row n) = b**c, where b(h) = 3*h-2, c(h) = n-1+h, n>=1, h>=1, and ** = convolution.
Original entry on oeis.org
1, 6, 2, 18, 11, 3, 40, 30, 16, 4, 75, 62, 42, 21, 5, 126, 110, 84, 54, 26, 6, 196, 177, 145, 106, 66, 31, 7, 288, 266, 228, 180, 128, 78, 36, 8, 405, 380, 336, 279, 215, 150, 90, 41, 9, 550, 522, 472, 406, 330, 250, 172, 102, 46
Offset: 1
Northwest corner (the array is read by falling antidiagonals):
1....6....18...40....75....126
2....11...30...62....110...177
3....16...42...84....145...228
4....21...54...106...180...279
5....26...66...128...215...330
-
b[n_]:=3n-2;c[n_]:=n;
t[n_,k_]:=Sum[b[k-i]c[n+i],{i,0,k-1}]
TableForm[Table[t[n,k],{n,1,10},{k,1,10}]]
Flatten[Table[t[n-k+1,k],{n,12},{k,n,1,-1}]]
r[n_]:=Table[t[n,k],{k,1,60}] (* A213771 *)
Table[t[n,n],{n,1,40}] (* A213772 *)
s[n_]:=Sum[t[i,n+1-i],{i,1,n}]
Table[s[n],{n,1,50}] (* A132117 *)
A176060
a(n) = n*(n+1)*(3*n^2+5*n+4)/12.
Original entry on oeis.org
0, 2, 13, 46, 120, 260, 497, 868, 1416, 2190, 3245, 4642, 6448, 8736, 11585, 15080, 19312, 24378, 30381, 37430, 45640, 55132, 66033, 78476, 92600, 108550, 126477, 146538, 168896, 193720, 221185, 251472, 284768, 321266, 361165, 404670, 451992
Offset: 0
For n=5, a(5)=1*(1*0+6)+2*(2*1+6)+3*(3*2+6)+4*(4*3+6)+5*(5*4+6)=260.
- "Supplemento al Periodico di Matematica", Raffaello Giusti Editore (Livorno), May 1908, p. 111 (Problem 923).
-
[n*(n+1)*(3*n^2+5*n+4)/12: n in [0..40]]; // Vincenzo Librandi, Jul 02 2011
-
Table[n(n+1)(3n^2+5n+4)/12,{n,0,40}] (* or *) LinearRecurrence[ {5,-10,10,-5,1},{0,2,13,46,120},40] (* Harvey P. Dale, Jul 14 2011 *)
A178067
Triangle read by rows: T(n,k) = (n^2 + k)*(n - k + 1)/2.
Original entry on oeis.org
1, 5, 3, 15, 11, 6, 34, 27, 19, 10, 65, 54, 42, 29, 15, 111, 95, 78, 60, 41, 21, 175, 153, 130, 106, 81, 55, 28, 260, 231, 201, 170, 138, 105, 71, 36, 369, 332, 294, 255, 215, 174, 132, 89, 45, 505, 459, 412, 364, 315, 265, 214, 162, 109, 55, 671, 615, 558, 500, 441, 381, 320, 258, 195, 131, 66
Offset: 1
First few rows of the triangle:
1;
5, 3;
15, 11, 6;
34, 27, 19, 10;
65, 54, 42, 29, 15;
111, 95, 78, 60, 41, 21;
175, 153, 130, 106, 81, 55, 28;
260, 231, 201, 170, 138, 105, 71, 36;
369, 332, 294, 255, 215, 174, 132, 89, 45;
505, 459, 412, 364, 315, 265, 214, 162, 109, 55;
671, 615, 558, 500, 441, 381, 320, 258, 195, 131, 66;
...
Example: Row 3 = (15, 11 6) since row 3 of A000027 as a triangle = (4, 5, 6); then taking partial sums from the right.
Name changed and terms a(37) and beyond from
Andrew Howroyd, Apr 17 2021
Showing 1-5 of 5 results.
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