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A349523
a(n) = Sum_{k=1..n} A339399(k).
0
1, 2, 3, 5, 6, 9, 11, 13, 14, 18, 20, 23, 24, 29, 31, 35, 38, 41, 42, 48, 50, 55, 58, 62, 63, 70, 72, 78, 81, 86, 90, 94, 95, 103, 105, 112, 115, 121, 125, 130, 131, 140, 142, 150, 153, 160, 164, 170, 175, 180, 181, 191, 193, 202, 205, 213, 217, 224, 229, 235, 236, 247, 249
OFFSET
1,2
COMMENTS
Partial sums of A339399.
FORMULA
a(n) = Sum_{i=1..n} ((1+(-1)^i)*(1+floor(sqrt(2*i-1-(-1)^i)))/2-((2*i+1-(-1)^i)/2-2 *Sum_{k=1..floor(sqrt(2*i-2-(-1)^i)-1)} floor((k+1)/2))*(-1)^i/2).
a(n) = Sum_{k=1..n} A339443(A103889(k)).
MATHEMATICA
Table[Sum[((1 + (-1)^k) (1 + Floor[Sqrt[2 k - 1 - (-1)^k]])/2 - ((2 k + 1 - (-1)^k)/2 - 2 Sum[Floor[(i + 1)/2], {i, -1 + Floor[Sqrt[2 k - 2 - (-1)^k]]}]) (-1)^k/2), {k, n}], {n, 100}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Wesley Ivan Hurt, Nov 20 2021
STATUS
approved