A158993 - OEIS

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A158993

Numbers n such that n=phi(n/d_1)+phi(n/d_2)+...+phi(n/d_k) where d_1 d_2 ... d_k is the decimal expansion of n.

1, 211896, 61341696, 141732864, 219483432, 1423392768, 4844814336, 16484622336, 23362267824, 28193299344, 169699442688, 993338339328, 2344883866416, 8829641374848, 423732883488768

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OFFSET

1,2

COMMENTS

There is no further term up to 3.6*10^9.

There is no further term up to 10^10. [From Farideh Firoozbakht, Jul 24 2009]

LINKS

Table of n, a(n) for n=1..15.

EXAMPLE

211896=phi(211896/2)+phi(211896/1)+phi(211896/1)+phi(211896/8)+phi(211896/9)+phi(211896/6) so 211896 is in the sequence.

eulerphi(16484622336/1)+eulerphi(16484622336/6)+eulerphi(16484622336/4)+eulerphi (16484622336/8)+eulerphi(16484622336/4)+eulerphi(16484622336/6)+eulerphi(1648462 2336/2)+eulerphi(16484622336/2)+eulerphi(16484622336/3)+eulerphi(16484622336/3)+ eulerphi(16484622336/6)=16484622336 Qu,shun liang (medie2006(AT)126.com), Aug 18 2009

MATHEMATICA

Do[h=IntegerDigits[n]; l=Length[h]; If[Min[h]>0&&Union[Mod[n, h]]=={0}&&n==Sum[EulerPhi[n/h[[k]]]

, {k, l}], Print[n]], {n, 2000000000}]

CROSSREFS

Sequence in context: A259756 A251511 A252880 * A231418 A246999 A186694

Adjacent sequences: A158990 A158991 A158992 * A158994 A158995 A158996

KEYWORD

base,more,nonn

AUTHOR

Farideh Firoozbakht, Jul 18 2009

EXTENSIONS

One more term from Farideh Firoozbakht, Jul 24 2009

Terms from 16484622336 through 423732883488768 from Qu,shun liang (medie2006(AT)126.com), Aug 18 2009

STATUS

approved