A066359 Nonsquarefree numbers n such that phi(n) = phi(n-2)-phi(n-1), where phi is Euler's totient function.

46795, 78183, 112995, 1986975, 2411175, 2689695, 2744145, 3619071, 3712545, 4738185, 8184715, 12176109, 13342959, 26400843, 33789015, 40425645, 61114185, 78464475, 83333565, 167077575, 212066541, 248682015, 326834725, 336828205, 353707705, 391078425, 880254585

Offset

1,1

Comments

See comment in A066232.

Numbers in A066232 that are not squarefree.

Links

Table of n, a(n) for n=1..27.

Prog

(PARI) ph1=1; ph2=1; for(n=3, 880254585, ph3=eulerphi(n); if(issquarefree(n)==0, if(ph3==ph1-ph2, print1(n ", "))); ph1=ph2; ph2=ph3) /* Donovan Johnson, Oct 20 2012 */

Crossrefs

Sequence in context: A205474 A232411 A171103 * A234774 A236053 A109030

Adjacent sequences: A066356 A066357 A066358 * A066360 A066361 A066362

Keyword

nonn

Author

Jason Earls, Dec 20 2001

Extensions

a(10)-a(27) from Donovan Johnson, Oct 20 2012

Status

approved