A360965 Array T(n,m) = (2^(n*m)-1)/(2^m-1) read by antidiagonals, n,m>=1.

1, 1, 3, 1, 5, 7, 1, 9, 21, 15, 1, 17, 73, 85, 31, 1, 33, 273, 585, 341, 63, 1, 65, 1057, 4369, 4681, 1365, 127, 1, 129, 4161, 33825, 69905, 37449, 5461, 255, 1, 257, 16513, 266305, 1082401, 1118481, 299593, 21845, 511, 1, 513, 65793, 2113665, 17043521, 34636833, 17895697, 2396745, 87381, 1023

Offset: 1

Author

R. J. Mathar, Feb 27 2023

Keywords

• nonn
• tabl
• easy

Examples

			The array starts in rows n>=1 and columns m>=1 as
   1    1    1     1       1
   3    5    9    17      33
   7   21   73   273    1057
  15   85  585  4369   33825
  31  341 4681 69905 1082401
		

Links

• Quynh Nguyen, Jean Pedersen, and Hien T. Vu, New Integer Sequences Arising From 3-Period Folding Numbers, JIS vol 19 (2016) #16.3.1 table 1.

Crossrefs

Cf. A000225 (first col), A002450 (2nd col), A023001 (3rd col)

Formula

T(n,m) = (2^(n*m)-1)/(2^m-1) for n>1.