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A039768 GCD(phi(a(n)),a(n)-1) = number of divisors of (a(n)-1). 0
2, 3, 105, 133, 153, 185, 345, 377, 425, 585, 637, 665, 777, 805, 825, 873, 897, 905, 949, 1017, 1090, 1113, 1209, 1225, 1261, 1305, 1309, 1385, 1449, 1525, 1545, 1573, 1645, 1681, 1785, 1813, 1833, 1865, 1885, 1957, 1981, 2009, 2057, 2077, 2105 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..45.

EXAMPLE

phi(105)=48, gcd(48,104)=8, 104 is divisible by {1,2,4,8,13,26,52,104}.

CROSSREFS

Cf. A000005, A000010.

Sequence in context: A256114 A062657 A041589 * A097653 A164926 A129729

Adjacent sequences:  A039765 A039766 A039767 * A039769 A039770 A039771

KEYWORD

nonn,easy

AUTHOR

Olivier Gérard

STATUS

approved

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Last modified March 28 05:07 EDT 2017. Contains 284182 sequences.