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A259365 Numbers n such that phi(Rev(n)) - phi(n) = n. 0
28, 139872, 2764928, 34141176, 329774256 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

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

LINKS

Table of n, a(n) for n=1..5.

FORMULA

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

EXAMPLE

phi(82) - phi(28) = 40 - 12 = 28;

phi(278931) - phi(139872) = 184032 - 44160 = 139872; etc.

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);

CROSSREFS

Cf. A000010, A004086, A097647.

Sequence in context: A159443 A119162 A180067 * A047680 A090768 A119180

Adjacent sequences:  A259362 A259363 A259364 * A259366 A259367 A259368

KEYWORD

nonn,more,base

AUTHOR

Paolo P. Lava, Jun 25 2015

STATUS

approved

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Last modified October 19 03:24 EDT 2019. Contains 328211 sequences. (Running on oeis4.)