cp's OEIS Frontend

A244425 Consider the sequence of almost natural numbers (A007376) and arrange it in a table by antidiagonals; sequence gives the main diagonal.

%I A244425 #22 Dec 01 2014 00:20:20
%S A244425 1,5,1,7,5,5,7,1,7,5,1,1,1,5,1,1,1,2,2,9,3,3,7,4,4,7,5,5,7,6,6,9,7,7,
%T A244425 3,8,9,7,8,7,7,8,0,3,7,2,8,5,3,2,2,3,5,8,2,7,3,0,8,7,7,8,0,3,7,2,8,5,
%U A244425 3,2,2,3,5,8,2,7,3,0,8,7,7,8,0,3,7,2,8,5,3,2,2,3,5,8,2,7,3,0,8,7,7,8,0,3,7
%N A244425 Consider the sequence of almost natural numbers (A007376) and arrange it in a table by antidiagonals; sequence gives the main diagonal.
%C A244425 The table is:
%C A244425 1, 2, 4, 7, 0, 1, 1, 9, 3, 2,
%C A244425 3, 5, 8, 1, 3, 6, 2, 2, 8, 3,
%C A244425 6, 9, 1, 1, 1, 0, 4, 2, 3, 9,
%C A244425 1, 1, 4, 7, 2, 2, 9, 4, 4, 4,
%C A244425 2, 1, 1, 1, 5, 3, 3, 0, 6, 5,
%C A244425 5, 8, 2, 2, 0, 5, 4, 4, 3, 0,
%C A244425 1, 2, 6, 3, 3, 1, 7, 5, 6, 8,
%C A244425 2, 2, 1, 6, 4, 4, 4, 1, 6, 7,
%C A244425 7, 3, 3, 2, 8, 5, 6, 9, 7, 8,
%C A244425 2, 7, 4, 4, 5, 2, 7, 7, 6, 5, ...
%F A244425 a(n) = A007376(A001844(n-1)). - _Omar E. Pol_, Jun 29 2014
%t A244425 almostNatural[n_, b_] := 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_, m_] := (n + m - 2) (n + m - 1)/2 + m; Array[ almostNatural[ f[#, #], 10] &, 105] (* modified Jun 29 2014 *)
%Y A244425 Cf. A007376, A033307, A001844, A244426.
%K A244425 nonn,base,tabl
%O A244425 1,2
%A A244425 _Robert G. Wilson v_, Jun 27 2014