A083657 a(n) = Sum_{i=1..n} floor(r*floor(r*i)) where r=sqrt(3).
1, 6, 14, 24, 37, 54, 74, 96, 121, 150, 182, 216, 254, 295, 338, 384, 434, 487, 542, 600, 662, 727, 794, 865, 939, 1016, 1095, 1178, 1264, 1352, 1443, 1538, 1636, 1736, 1839, 1946, 2056, 2168, 2284, 2403, 2525, 2649, 2777, 2908, 3041, 3177, 3317, 3460, 3605
Offset: 1
Keywords
Crossrefs
Partial sums of A022158.
Programs
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PARI
a(n) = sum(i=1, n, floor(sqrt(3)*floor(sqrt(3)*i))); \\ Michel Marcus, Dec 05 2013
Formula
a(n) = (n/2)*(3n-1)+ n/sqrt(3) + O(1).