OFFSET
1,1
LINKS
Giovanni Resta, Table of n, a(n) for n = 1..50
EXAMPLE
25 = concat(2,5); phi(25) + phi(2) + phi(5) = 20 + 1 + 4 = 25;
177 = concat(1,77); phi(177) + phi(1) + phi(77) = 116 + 1 + 60 = 177; etc.
MAPLE
with(numtheory); P:=proc(q) local a, b, i; global n; for n from 1 to q do
for i from 1 to ilog10(n) do a:=trunc(n/10^i); b:=n-a*10^i;
if a>0 and b>0 then if phi(n)+phi(a)+phi(b)=n
then print(n); break; fi; fi; od; od; end: P(10^9);
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Paolo P. Lava, May 26 2015
EXTENSIONS
a(18) inserted by Giovanni Resta, May 27 2015
STATUS
approved