This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A322550 #27 Jun 24 2024 15:53:10 %S A322550 1,4,2,9,1,3,16,18,12,4,25,4,1,2,5,36,50,48,36,20,6,49,9,75,1,45,3,7, %T A322550 64,98,4,100,80,2,28,8,81,16,147,18,1,12,63,4,9,100,162,192,196,180, %U A322550 150,112,72,36,10,121,25,9,4,245,1,175,2,3,5,11,144,242,300,324,320,294,252,200,144,90,44,12 %N A322550 Table read by ascending antidiagonals: T(n, k) is the minimum number of cubes necessary to fill a right square prism with base area n^2 and height k. %H A322550 Stefano Spezia, <a href="/A322550/b322550.txt">First 150 antidiagonals of the table, flattened</a> %F A322550 T(n, k) = n^2*k/gcd(n, k)^3. %F A322550 T(n, k) = A000290(n)*k/A000578(A050873(n,k)). %F A322550 X(n, k) = T(n + 1 - k, k). %F A322550 X(2*n - 1, n) = A000012(n). %F A322550 Product_{k=1..n} X(n, k)^(1/3) = A119619(n+1). - _Stefano Spezia_, Jun 24 2024 %e A322550 The table T starts in row n = 1 with columns k >= 1 as: %e A322550 1 2 3 4 5 6 7 8 9 ... %e A322550 4 1 12 2 20 3 28 4 36 ... %e A322550 9 18 1 36 45 2 63 72 3 ... %e A322550 16 4 48 1 80 12 112 2 144 ... %e A322550 25 50 75 100 1 150 175 200 225 ... %e A322550 36 9 4 18 180 1 252 36 12 ... %e A322550 49 98 147 196 245 294 1 392 441 ... %e A322550 64 16 192 4 320 48 448 1 576 ... %e A322550 81 162 9 324 405 18 567 648 1 ... %e A322550 ... %e A322550 The triangle X(n, k) begins %e A322550 n\k| 1 2 3 4 5 6 7 8 9 %e A322550 ---+---------------------------------------------------- %e A322550 1 | 1 %e A322550 2 | 4 2 %e A322550 3 | 9 1 3 %e A322550 4 | 16 18 12 4 %e A322550 5 | 25 4 1 2 5 %e A322550 6 | 36 50 48 36 20 6 %e A322550 7 | 49 9 75 1 45 3 7 %e A322550 8 | 64 98 4 100 80 2 28 8 %e A322550 9 | 81 16 147 18 1 12 63 4 9 %e A322550 ... %p A322550 a := (n, k) -> (n+1-k)^2*k/gcd(n+1-k, k)^3: seq(seq(a(n, k), k = 1 .. n), n = 1 .. 12) %t A322550 T[n_,k_]:=n^2*k/GCD[n,k]^3; Flatten[Table[T[n-k+1,k], {n, 12}, {k, n}]] %o A322550 (GAP) Flat(List([1..12], n->List([1..n], k->(n+1-k)^2*k/GcdInt(n+1-k,k)^3))); %o A322550 (Magma) [[(n+1-k)^2*k/Gcd(n+1-k,k)^3: k in [1..n]]: n in [1..12]]; // triangle output %o A322550 (Maxima) sjoin(v, j) := apply(sconcat, rest(join(makelist(j, length(v)), v)))$ display_triangle(n) := for i from 1 thru n do disp(sjoin(makelist((i+1-j)^2*j/gcd(i+1-j,j)^3, j, 1, i), " ")); display_triangle(12); %o A322550 (PARI) %o A322550 T(n, k) = (n+1-k)^2*k/gcd(n+1-k,k)^3; %o A322550 tabl(nn) = for(i=1, nn, for(j=1, i, print1(T(i, j), ", ")); print); %o A322550 tabl(12) \\ triangle output %Y A322550 Cf. A000012 (main diagonal of the table), A000027 (1st row of the table or diagonal of the triangle), A000290 (k=1), A000578, A011379 (superdiagonal of the table), A045991 (subdiagonal of the table), A050873, A119619, A320043 (row sums of the triangle). %K A322550 nonn,tabl %O A322550 1,2 %A A322550 _Stefano Spezia_, Dec 15 2018