A244810 The hexagonal spiral of Champernowne, read along the North (or 360-degree) ray.

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

Links

Table of n, a(n) for n=1..105.

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]

Crossrefs

Cf. A007376, A244803, A244807, A244808, A244809, A244811, A244812, A244813, A244814, A244815, A244816, A244817, A244818.

Sequence in context: A330111 A335822 A233033 * A273985 A347195 A132036

Adjacent sequences: A244807 A244808 A244809 * A244811 A244812 A244813

Keyword

nonn,easy

Author

Robert G. Wilson v, Jul 06 2014

Status

approved