Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #6 Jul 05 2014 17:00:47
%S 1,1,4,7,1,6,2,9,7,4,6,7,7,2,0,6,9,1,5,0,2,2,1,7,3,2,9,7,2,3,8,9,9,4,
%T 8,5,4,5,0,3,7,6,3,4,8,8,7,7,7,9,0,4,3,1,1,1,3,4,2,1,3,2,5,4,1,5,1,6,
%U 6,1,7,0,7,9,1,0,9,8,1,2,2,8,9,4,2,5,7,0,6,2,8,6,1,9,3,1,5,2,2,3,4,4,3,6,3
%N The spiral of Champernowne read by the North-Northeast ray.
%F See A244677 formula section.
%e See A244677 for the spiral of David Gawen Champernowne.
%t almostNatural[n_, b_] := Block[{m = 0, d = n, i = 1, l, p}, While[m <= d, l = m; m = (b - 1) i*b^(i - 1) + l; i++]; i--; p = Mod[d - l, i]; q = Floor[(d - l)/i] + b^(i - 1); If[p != 0, IntegerDigits[q, b][[p]], Mod[q - 1, b]]]; f[n_] := 16n^2 - 35n + 20 (* see A244677 formula section *); Array[ almostNatural[ f@#, 10] &, 105]
%Y Cf. A033307, A033952, A143861, A244677 - A244688, A244690 - A244692.
%K nonn,easy
%O 1,3
%A _Robert G. Wilson v_, Jul 04 2014