A259365 Numbers n such that phi(Rev(n)) - phi(n) = n.

28, 139872, 2764928, 34141176, 329774256

Offset: 1

Author

Paolo P. Lava, Jun 25 2015

Keywords

• nonn
• more
• base

Comments

a(6) > 3*10^10. - Giovanni Resta, Jun 26 2015

Examples

			phi(82) - phi(28) = 40 - 12 = 28;
phi(278931) - phi(139872) = 184032 - 44160 = 139872; etc.
		

Crossrefs

Cf. A000010, A004086, A097647.

Programs

Maple

with(numtheory): T:=proc(w) local x,y,z; x:=w; y:=0;
for z from 1 to ilog10(x)+1 do
y:=10*y+(x mod 10); x:=trunc(x/10); od; y; end:
P:=proc(q) local a,j,k,n; for n from 1 to q do
if phi(T(n))-phi(n)=n then print(n); fi; od; end: P(10^9);

Formula

Solutions of the equation A000010( A004086(n) ) - A000010(n) = n.