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A227429 Numbers n such that sum_{i=1..n} i^phi(i) == 0 (mod n). 8
1, 3, 4, 12, 21, 39, 91, 156, 381, 1668, 3292, 4541, 6515, 12927, 49492, 72412 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(17) > 10^5. - Giovanni Resta, Jul 11 2013

LINKS

Table of n, a(n) for n=1..16.

EXAMPLE

1^phi(1) + 2^phi(2) + … + 11^phi(11) + 12^phi(12) = 1^1 + 2^1 + 3^2 + 4^2 + 5^4 + 6^2 + 7^6 + 8^4 + 9^6 + 10^4+ 11^10 + 12^4 = 25938109212 and 25938109212 / 12 = 2161509101.

MAPLE

with(numtheory); ListA227429:=proc(q) local i, n;

for n from 1 to q do if add(i^phi(i), i=1..n) mod n=0 then print(n);

fi; od; end: ListA227429(10^6);

CROSSREFS

Cf. A000010, A227427

Sequence in context: A281892 A101727 A292551 * A075220 A075221 A295948

Adjacent sequences:  A227426 A227427 A227428 * A227430 A227431 A227432

KEYWORD

nonn

AUTHOR

Paolo P. Lava, Jul 11 2013

EXTENSIONS

a(10)-a(16) from Giovanni Resta, Jul 11 2013

STATUS

approved

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Last modified November 18 15:55 EST 2018. Contains 317323 sequences. (Running on oeis4.)