A104611 Write the natural numbers in base 7 in a triangle with k digits in the k-th row, as shown below. Sequence gives the leading diagonal.

1, 3, 6, 1, 1, 2, 3, 0, 3, 4, 1, 0, 1, 4, 2, 1, 6, 5, 1, 4, 4, 2, 5, 6, 2, 2, 4, 3, 2, 5, 3, 5, 2, 4, 4, 2, 5, 6, 5, 5, 4, 4, 6, 0, 2, 1, 3, 1, 1, 3, 1, 2, 2, 1, 1, 1, 1, 5, 4, 4, 4, 1, 1, 3, 1, 2, 6, 0, 2, 2, 3, 0, 2, 1, 2, 2, 2, 2, 0, 6, 2, 2, 5, 6, 4, 3, 6, 0, 3, 6, 2, 2, 2, 3, 0, 3, 3, 5, 6, 6, 2, 4, 3, 1, 4

Offset: 1

Author

Robert G. Wilson v, Mar 16 2005

Keywords

• base
• nonn

Comments

1

23

456

1011

12131

415162...

Crossrefs

Cf. A104606, A104607, A104608, A104609, A104610, A104612, A104613, A091425, A104614, A104615, A104616, A104617, A104618, A104619, A104620.

Programs

Mathematica

t = Flatten[ IntegerDigits[ Range[1500], 7]]; t[[Table[n(n + 1)/2, {n, 105}]]]
Module[{d = Flatten[Table[IntegerDigits[n, 7], {n, 2000}]]}, TakeList[ d, Range[(Sqrt[8*Length[d] + 1] - 1)/2]]][[All, -1]] (* Requires Mathematica version 11 or later *) (* Harvey P. Dale, Jul 09 2020 *)