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A368612
a(n) = Sum_{k=2..n} pi(k-1) * ceiling(n/k).
4
0, 0, 1, 4, 8, 13, 20, 27, 37, 46, 56, 65, 81, 92, 107, 122, 140, 153, 175, 190, 214, 234, 254, 271, 304, 324, 347, 370, 399, 418, 454, 475, 509, 536, 564, 591, 635, 658, 689, 719, 763, 788, 835, 862, 904, 945, 981, 1010, 1070, 1103, 1148, 1185, 1231, 1262, 1318, 1356
OFFSET
1,4
FORMULA
a(n) = A368610(n) - A092494(n).
MATHEMATICA
Table[Sum[PrimePi[k - 1] Ceiling[n/k], {k, 2, n}], {n, 100}]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Wesley Ivan Hurt, Dec 31 2023
STATUS
approved