login
A244810
The hexagonal spiral of Champernowne, read along the North (or 360-degree) ray.
11
1, 1, 8, 5, 9, 3, 1, 0, 9, 3, 3, 1, 6, 8, 1, 9, 1, 4, 2, 1, 2, 9, 7, 1, 9, 4, 2, 2, 2, 9, 9, 3, 1, 3, 7, 3, 6, 7, 6, 4, 7, 1, 5, 5, 4, 4, 6, 6, 7, 6, 7, 8, 6, 9, 0, 9, 1, 0, 0, 4, 0, 1, 4, 1, 9, 2, 6, 9, 3, 4, 3, 3, 6, 4, 9, 5, 0, 4, 6, 4, 7, 9, 3, 8, 9, 9, 9, 3, 0, 4, 1, 0, 5, 2, 9, 3, 3, 7, 5, 4, 6, 6, 1, 7, 9
OFFSET
1,3
FORMULA
(12n^2 - 25n + 14)th almost natural number (A033307), Also see formula section of A056105.
EXAMPLE
see A244807 example section for its diagram.
MATHEMATICA
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_] := 12n^2 - 25n + 14 (* see formula section of A244807 *); Array[ almostNatural[ f@#, 10] &, 105]
KEYWORD
nonn,easy
AUTHOR
Robert G. Wilson v, Jul 06 2014
STATUS
approved