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Partial sums of A004144.
0

%I #16 Aug 29 2020 07:59:21

%S 1,3,6,10,16,23,31,40,51,63,77,93,111,130,151,173,196,220,247,275,306,

%T 338,371,407,445,487,530,574,620,667,715,764,818,874,931,990,1052,

%U 1115,1179,1245,1312,1381,1452,1524,1600,1677,1756,1837,1920,2004,2090,2178

%N Partial sums of A004144.

%F a(n) = Sum_{i=1..n} A004144(i).

%t fQ[n_] := If[n > 1, First@ Union@ Mod[ First@# & /@ FactorInteger@ n, 4] != 1, True]; Accumulate@ Select[ Range@ 90, fQ]

%Y Cf. A004144.

%K nonn

%O 1,2

%A _Jonathan Vos Post_, Sep 19 2010

%E a(21) and a(50) corrected by _Georg Fischer_, Aug 29 2020