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A140435
Number of new lattice points created at each step in an n X n grid that are not visible.
1
0, 1, 1, 3, 1, 7, 1, 7, 5, 11, 1, 15, 1, 15, 13, 15, 1, 23, 1, 23, 17, 23, 1, 31, 9, 27, 17, 31, 1, 43, 1, 31, 25, 35, 21, 47, 1, 39, 29, 47, 1, 59, 1, 47, 41, 47, 1, 63, 13, 59, 37, 55, 1, 71, 29, 63, 41, 59, 1, 87, 1, 63, 53, 63, 33, 91, 1, 71, 49, 91, 1, 95, 1, 75, 69, 79, 33, 107, 1, 95, 53
OFFSET
1,4
FORMULA
G.f.: -Sum_{k>=2} mu(k) * x^k * (1 + x^k) / (1 - x^k)^2. - Ilya Gutkovskiy, Sep 14 2021
MATHEMATICA
g[n_] := Table[ #^2 &[m], {m, 1, n + 1}] - FoldList[Plus, 1, 2 Array[EulerPhi, n, 2]] - Most[Flatten[ Append[{0}, Table[ #^2 &[m], {m, 1, n + 1}] - FoldList[Plus, 1, 2 Array[EulerPhi, n, 2]]]]]; g[80]
CROSSREFS
Sequence in context: A186428 A323599 A167515 * A194181 A277934 A063754
KEYWORD
nonn
AUTHOR
Gregg Whisler, Jun 25 2008
EXTENSIONS
More terms from Robert G. Wilson v, Jan 17 2011
STATUS
approved