A067120 a(n) = floor(X/Y) where X = concatenation of first n odd numbers in increasing order and Y = n-th triangular number.

1, 4, 22, 135, 905, 64662, 4849682, 377197536, 30175802922, 2468929330031, 205744110835938, 17409117070733232, 1492210034634277058, 129324869668304011738, 11315926095976601027106, 998464067292053031803477, 88752361537071380604753549, 7941000769106386685688475516

Offset: 1

Author

Amarnath Murthy, Jan 08 2002

Keywords

• easy
• nonn
• base
• less

Examples

			a(4) floor[1357/(1+2+3+4)] = floor[135.7] = 135.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..353

Crossrefs

Cf. A067112-A067119.

Programs

Maple

for i from 1 to 33 do n := 2*i-1:c := n:n := n-2:while(n>0) do g := floor(log(c)/log(10)):c := c+10^(g+1)*n:n := n-2:end do:a[i] := floor(2*c/i/(i+1)):end do:q2 := seq(a[j],j=1..33);

Mathematica

With[{nn=20},Table[Floor[FromDigits[Flatten[IntegerDigits/@Range[1,2n-1,2]]]/((n(n+1))/2)],{n,nn}]] (* Harvey P. Dale, Feb 22 2020 *)

Extensions

More terms from Sascha Kurz, Mar 23 2002

Edited by Charles R Greathouse IV, Apr 27 2010