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A066219
Numbers n such that |phi(n+1)-phi(n)| = |d(n+1)-d(n)|, where phi is Euler's totient function and d(n) = number of divisors of n.
0
5, 7, 45, 104, 105, 345, 1754, 3255, 16215, 17534, 22935, 67431, 70634, 93074, 983775, 1025504, 1156701, 2200694, 2619705, 2745765, 3365438, 4163355, 4447064, 4695704, 6372794, 7838265, 9718904, 11903775, 23992215, 26879684, 29357475, 37239735, 40588485
OFFSET
1,1
EXAMPLE
|phi(6)-phi(5)| = |2-4| = |d(6)-d(5)| = |4-2|
PROG
(PARI) ph1=1; d1=1; for(n=1, 40588485, ph2=eulerphi(n+1); d2=numdiv(n+1); if(abs(ph2-ph1)==abs(d2-d1), print1(n ", ")); ph1=ph2; d1=d2) /* Donovan Johnson, Oct 19 2012 */
CROSSREFS
Sequence in context: A213175 A265786 A090520 * A278618 A174267 A306649
KEYWORD
nonn
AUTHOR
Joseph L. Pe, Dec 17 2001
EXTENSIONS
a(7)-a(33) from Donovan Johnson, Oct 19 2012
STATUS
approved