|
|
A082190
|
|
Antidiagonal sums of square array A082025.
|
|
5
|
|
|
1, 5, 16, 39, 79, 157, 190, 337, 407, 705, 742, 1147, 1235, 1855, 1836, 2879, 2691, 4067, 3752, 5683, 5005, 7687, 6670, 10117, 8595, 12837, 10950, 15737, 13461, 19621, 16494, 23739, 19925, 28401, 23788, 34057, 28077, 39997, 32842, 47027, 38309
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
LINKS
|
|
|
MAPLE
|
b:= proc(t) option remember; false end: b(1):= true: ncpr:= proc() local i, m; m:= args[1]; for i from 2 to nargs do if igcd (m, args[i])<>1 then return true fi od; false end: T:= proc(n, k) option remember; local h, t, l; if n<1 or k<1 or n=1 and k=1 then t:=1 else h:= 1- 2* irem(n+k, 2); l:= T(n-1, k), T(n, k-1), T(n-1, k-1), T(n+h, k-h); for t while b(t) or ncpr(t, l) do od fi; b(t):= true; t end: seq(add(T(n, 1+d-n), n=1..d), d=1..60); # Alois P. Heinz, Oct 07 2009
|
|
MATHEMATICA
|
dmax = 50 (* number of antidiagonals *);
a[1, 1] = 1; used = {1}; a[_, _] = 1;
loop := For[i = d - j + 1; k = 1, True, k++, If[FreeQ[used, k] && AllTrue[ {a[i - 1, j + 1], a[i - 1, j], a[i - 1, j - 1], a[i, j - 1], a[i + 1, j - 1]}, CoprimeQ[k, #] &], AppendTo[used, k]; a[i, j] = k; Break[]]];
Do[If[EvenQ[d], Do[loop, {j, d, 1, -1}], Do[loop, {j, 1, d}]], {d, 2, dmax}];
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|