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.

A348835 Triangle, read by rows, T(n, k) is the smallest term of A006005 strictly larger than abs(A006005(n) - A006005(k)).

Original entry on oeis.org

1, 3, 1, 5, 3, 1, 7, 5, 3, 1, 11, 11, 7, 5, 1, 13, 11, 11, 7, 3, 1, 17, 17, 13, 11, 7, 5, 1, 19, 17, 17, 13, 11, 7, 3, 1, 23, 23, 19, 17, 13, 11, 7, 5, 1, 29, 29, 29, 23, 19, 17, 13, 11, 7, 1, 31, 29, 29, 29, 23, 19, 17, 13, 11, 3, 1, 37, 37, 37, 31, 29, 29, 23, 19, 17, 11, 7, 1
Offset: 1

Views

Author

Michel Marcus, Nov 01 2021

Keywords

Examples

			Triangle begins:
   1;
   3,  1;
   5,  3,  1;
   7,  5,  3,  1;
  11, 11,  7,  5, 1;
  13, 11, 11,  7, 3, 1;
  17, 17, 13, 11, 7, 5, 1;
  ...
		

Crossrefs

Cf. A006005 (1 and the odd primes).

Programs

  • PARI
    f(n) = prime(n)-(n==1); /* A006005 */
    T(n, k) = {my(j=1, m = abs(f(n)-f(k))); while (f(j) < m, j++); f(j);}

Formula

T(n, n) = 1.
T(n, 1) = n.