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%I #17 Oct 08 2017 23:46:30
%S 1,4,4,4,8,4,4,8,8,4,8,4,8,12,8,8,4,8,4,8,8,8,8,4,12,8,8,8,8,4,16,8,4,
%T 8,8,8,4,8,16,8,8,8,4,12,8,8,8,8,8,8,8,4,8,16,4,16,8,8,4,16,8,8,8,8,8,
%U 8,4,8,12,16,8,8,8,8,16,8,8,4,8,12,8,16,8,8,8,16,12,8,8,8,8,8,8,4,8,8,16,4
%N Numbers of points on successive rings of the simple square lattice.
%C This is A004018 with the zero terms omitted.
%C a(n) = A004018(A001481(n)). - _Franz Vrabec_, Jun 14 2005
%H T. D. Noe, <a href="/A105352/b105352.txt">Table of n, a(n) for n = 1..10000</a>
%e a(1) = 1 from (0, 0).
%e a(2) = 4 from (0, 1), (0, -1), (1, 0), (-1, 0).
%e a(5) = 8 from (+-1, +-2), (+-2, +-1).
%t max = 100; A001481 = Select[Range[0, 4*max], SquaresR[2, #] != 0 &]; A004018[n_] := SquaresR[2, n]; a[n_] := A004018[A001481[[n]]]; Table[a[n], {n, 1, max}] (* _Jean-François Alcover_, Oct 04 2013, after _Franz Vrabec_ *)
%Y Cf. A004018, A001481; A057961 (partial sums).
%K nice,nonn
%O 1,2
%A _Sébastien Dumortier_, Apr 30 2005
%E Definition revised by _N. J. A. Sloane_, Oct 04 2013
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