A116044 n+phi(n)+phi(phi(n)) is a palindrome.

1, 2, 3, 4, 5, 6, 14, 23, 28, 45, 51, 55, 56, 63, 75, 79, 85, 95, 136, 138, 146, 161, 168, 169, 186, 189, 195, 201, 227, 231, 241, 247, 272, 274, 275, 276, 292, 297, 306, 322, 323, 336, 389, 398, 418, 423, 430, 444, 473, 504, 514, 543, 552, 555, 567, 574, 582

Offset

1,2

Links

Robert Israel, Table of n, a(n) for n = 1..2000

Example

227+phi(227)+phi(phi(227)) = 565.

Maple

filter:= proc(n) local t, x, L;
uses numtheory;
  t:= phi(n);
  x:= n + t + phi(t);
L:= convert(x, base, 10);
andmap(i -> L[i]=L[-i], [$1..nops(L)/2]);
end proc:
select(filter, [$1..1000]); # Robert Israel, Sep 03 2020

Crossrefs

Cf. A115905.

Sequence in context: A249102 A250047 A084830 * A116027 A085157 A065637

Adjacent sequences: A116041 A116042 A116043 * A116045 A116046 A116047

Keyword

nonn,base

Author

Giovanni Resta, Feb 13 2006

Status

approved