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A366955
a(n) is the Euler totient function of the concatenation of 1,2,3,...,n.
0
1, 4, 80, 616, 6576, 41088, 1224720, 4027392, 82260072, 4938271560, 635485074048, 41135376570624, 12236327748685824, 411522630337040436, 65843620853926470080, 6172839452588538935840, 805372326785629836739584, 40727551345036946357114880
OFFSET
1,2
FORMULA
a(n) = phi(A007908(n)) = A000010(A007908(n)).
CROSSREFS
Sequence in context: A211152 A093854 A345459 * A269146 A192834 A054322
KEYWORD
nonn,base
AUTHOR
Sean A. Irvine, Oct 29 2023
STATUS
approved