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A340080 a(n) = (1+A018804(n)) / gcd(n, 1+A018804(n)), where A018804(n) = Sum_{k=1..n} gcd(k, n). 3
2, 2, 2, 9, 2, 8, 2, 21, 22, 14, 2, 41, 2, 20, 46, 49, 2, 32, 2, 73, 22, 32, 2, 101, 66, 38, 82, 15, 2, 68, 2, 113, 106, 50, 118, 169, 2, 56, 42, 181, 2, 14, 2, 169, 38, 68, 2, 241, 134, 98, 166, 201, 2, 122, 38, 261, 62, 86, 2, 361, 2, 92, 274, 257, 226, 158, 2, 265, 226, 176, 2, 421, 2, 110, 326, 297, 274, 188 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..8191

Antti Karttunen, Data supplement: n, a(n) computed for n = 1..65537

FORMULA

a(n) = (1+A018804(n)) / gcd(n, 1+A018804(n)).

PROG

(PARI)

A018804(n) = sumdiv(n, d, n*eulerphi(d)/d); \\ From A018804

A340080(n) = { my(x=1+A018804(n)); x/gcd(n, x); };

CROSSREFS

Cf. A018804, A340078, A340079.

Sequence in context: A068718 A075097 A138056 * A022459 A060804 A086364

Adjacent sequences:  A340077 A340078 A340079 * A340081 A340082 A340083

KEYWORD

nonn

AUTHOR

Antti Karttunen, Dec 31 2020

STATUS

approved

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Last modified September 26 09:15 EDT 2021. Contains 347664 sequences. (Running on oeis4.)