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.

A130071 Triangle, A007444(k) in each column interspersed with k zeros.

Original entry on oeis.org

2, 2, 1, 2, 0, 3, 2, 1, 0, 4, 2, 0, 0, 0, 9, 2, 1, 3, 0, 0, 7, 2, 0, 0, 0, 0, 0, 15, 2, 1, 0, 4, 0, 0, 0, 12, 2, 0, 3, 0, 0, 0, 0, 0, 18, 2, 1, 0, 0, 9, 0, 0, 0, 0, 17
Offset: 1

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Author

Gary W. Adamson, May 05 2007

Keywords

Comments

Row sums = the primes. T(n,k) = 0 if k does not divide n. If k divides n, extract A007444(k) which become the nonzero terms of row n, sum = n-th prime. Example: The factors of 6 are (1, 2, 3 and 6) = k's for A007444(k) = (2 + 1 + 3 + 7) = p(6) = 13. A007444 = the Moebius transform of the primes, (2, 1, 3, 4, 9, 7, 15, 12, ...), as the right diagonal of A130071.

Examples

			First few rows of the triangle:
  2;
  2,  1;
  2,  0,  3;
  2,  1,  0,  4;
  2,  0,  0,  0,  9;
  2,  1,  3,  0,  0,  7;
  2,  0,  0,  0,  0,  0, 15;
  2,  1,  0,  4,  0,  0,  0, 12;
  2,  0,  3,  0,  0,  0,  0,  0, 18;
  2,  1,  0,  0,  9,  0,  0,  0,  0, 17;
  ...
		

Crossrefs

Formula

Given the Moebius transform of the primes, A007444: (2, 1, 3, 4, 9, 7, 15, ...), the k-th term (k= 1,2,3,...) of this sequence generates the k-th column of A130071, interspersed with (k-1) zeros.