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

Author

Jason Earls, Dec 20 2001

Keywords

• nonn

Comments

See comment in A066232.

Numbers in A066232 that are not squarefree.

Programs

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 */

Extensions

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