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A218259
a(n) = |{m : multiplicative order of n mod m = 10}|.
2
0, 5, 16, 38, 47, 40, 66, 84, 150, 33, 72, 10, 106, 178, 168, 140, 265, 54, 534, 106, 68, 20, 296, 56, 564, 231, 732, 52, 730, 26, 604, 114, 80, 164, 348, 332, 297, 50, 912, 84, 904, 110, 88, 130, 222, 552, 332, 76, 1430, 81, 702, 236, 950, 178, 256, 168, 564
OFFSET
1,2
LINKS
FORMULA
a(n) = tau(n^10-1)-tau(n^5-1)-tau(n^2-1)+tau(n-1), with tau = A000005.
MAPLE
with(numtheory):
a:= n-> add(mobius(10/d) *tau(n^d-1), d={1, 2, 5, 10}):
seq(a(n), n=1..80);
CROSSREFS
Row n=10 of A212957.
Sequence in context: A296536 A041044 A042645 * A211807 A174723 A011932
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Oct 24 2012
STATUS
approved