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A192221 Numbers n such that phi(n-2)=phi(n+2) where phi=A000010. 1
10, 16, 18, 22, 37, 54, 66, 93, 142, 150, 246, 294, 405, 457, 618, 630, 774, 803, 1013, 1026, 1110, 1146, 1254, 1272, 1297, 1458, 1590, 1686, 1822, 1830, 2032, 2166, 2454, 2625, 2646, 2662, 2694, 2934, 3030, 3218, 3323, 3510, 3990, 4266, 4342, 4374, 4614, 4806, 4854, 4950, 5182, 5286 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..52.

FORMULA

a(n) = A179186(n)+2. - R. J. Mathar, Jun 26 2011

MATHEMATICA

Select[Range[3, 5000], EulerPhi[# - 2] == EulerPhi[# + 2] &] (* Alonso del Arte, Jun 28 2011 *)

PROG

(PARI) for(n=3, 1e4, if(eulerphi(n-2)==eulerphi(n+2), print1(n", "))) \\ Charles R Greathouse IV, Jun 27 2011

CROSSREFS

Cf. A000010, A066812.

Sequence in context: A103208 A323196 A187797 * A106695 A053747 A228491

Adjacent sequences:  A192218 A192219 A192220 * A192222 A192223 A192224

KEYWORD

nonn

AUTHOR

Juri-Stepan Gerasimov, Jun 26 2011

STATUS

approved

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Last modified April 24 04:00 EDT 2019. Contains 322406 sequences. (Running on oeis4.)