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.

A167348 Let a(n) be the n-th term of the sequence. Let m = primorial(a(n)); m is the minimum positive integer such that m/phi(m) >= n.

Original entry on oeis.org

2, 2, 3, 7, 13, 23, 43, 79, 149, 257, 461, 821, 1451, 2549, 4483, 7879, 13859, 24247, 42683, 75037, 131707, 230773, 405401, 710569, 1246379, 2185021, 3831913, 6720059, 11781551, 20657677, 36221753, 63503639, 111333529, 195199289
Offset: 1

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Author

Fred Schneider, Aug 13 2009

Keywords

Comments

A variant of A091440, which is the main entry for this sequence.

Examples

			primorial(7) = 210; 210/phi(210) = 210/48 >= 4;
		

Crossrefs

Cf. A091440.

Programs

  • PARI
    al(lim) = local(mm,n,m); mm=3; n=2; m=1; forprime(x=3,lim, n*=x; m*= (x-1); if (n\m >= mm, print1(x","); mm++)); /* This will generate all terms of this sequence from the 3rd onward, up to lim. The computation slows down for large values because of the size of the internal values. */

Extensions

Edited and extended by Franklin T. Adams-Watters and N. J. A. Sloane, Aug 29 2009