cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A273136 Difference table of the divisors of the positive integers (with every table read by columns).

This page as a plain text file.
%I A273136 #14 Jun 29 2016 00:03:00
%S A273136 1,1,1,2,1,2,3,1,1,1,2,2,4,1,4,5,1,1,0,2,2,1,2,3,3,6,1,6,7,1,1,1,1,2,
%T A273136 2,2,4,4,8,1,2,4,3,6,9,1,1,2,0,2,3,2,5,5,10,1,10,11,1,1,0,0,1,1,2,1,0,
%U A273136 1,2,3,1,1,3,4,2,4,6,6,12,1,12,13,1,1,4,-2,2,5,2,7,7,14,1,2,0,8,3,2,8,5,10,15
%N A273136 Difference table of the divisors of the positive integers (with every table read by columns).
%C A273136 This is an irregular tetrahedron in which T(n,j,k) is the k-th element of the j-th column of the difference triangle of the divisors of n.
%C A273136 The first row of the slice n is also the n-th row of the triangle A027750.
%C A273136 The bottom entry of the slice n is A187202(n).
%C A273136 The number of elements in the n-th slice is A000217(A000005(n)) = A184389(n).
%C A273136 The sum of the elements of the n-th slice is A273103(n).
%C A273136 The columns sums give A273263.
%C A273136 If n is a power of 2 the subsequence lists the elements of the difference table of the divisors of n in nondecreasing order, for example if n = 8 the finite sequence of columns is [1, 1, 1, 1], [2, 2, 2], [4, 4], [8].
%C A273136 First differs from A273137 at a(86).
%e A273136 The tables of the first nine positive integers are
%e A273136 1; 1, 2; 1, 3; 1, 2, 4; 1, 5; 1, 2, 3, 6; 1, 7; 1, 2, 4, 8; 1, 3, 9;
%e A273136 .  1;    2;    1, 2;    4;    1, 1, 3;    6;    1, 2, 4;    2, 6;
%e A273136 .              1;             0, 2;             1, 2;       4;
%e A273136 .                             2;                1;
%e A273136 .
%e A273136 For n = 18 the difference table of the divisors of 18 is
%e A273136 1, 2, 3, 6, 9, 18;
%e A273136 1, 1, 3, 3, 9;
%e A273136 0, 2, 0, 6;
%e A273136 2, -2, 6;
%e A273136 -4, 8;
%e A273136 12;
%e A273136 This table read by columns gives the finite subsequence [1, 1, 0, 2, -4, 12], [2, 1, 2, -2, 8], [3, 3, 0, 6], [6, 3, 6], [9, 9], [18].
%t A273136 Table[Transpose@ Map[Function[w, PadRight[w, Length@ #]], NestWhileList[Differences, #, Length@ # > 1 &]] &@ Divisors@ n, {n, 15}] /. 0 -> {} // Flatten (* _Michael De Vlieger_, Jun 26 2016 *)
%Y A273136 Cf. A000005, A000217, A027750, A184389, A187202, A272210, A273102, A273103, A273135, A273137, A273263.
%K A273136 sign,tabf
%O A273136 1,4
%A A273136 _Omar E. Pol_, Jun 26 2016