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A143356

1, 4, 6, 12, 11, 23, 17, 32, 29, 41, 30, 66, 38, 61, 61, 82, 53, 104, 61, 115, 92, 107, 77, 170, 98, 132, 124, 170, 104, 216, 114, 201, 158, 183, 158, 287, 143, 210, 193, 293, 161, 318, 171, 291, 266, 266, 189, 418, 218, 335, 269, 357, 220, 426, 271, 429, 309, 354, 250

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..59.

FORMULA

Inverse Mobius transform (A051731) of A006218. Row sums of triangle A143355.

a(n) = Sum_{i=1..n} tau(i)*A135539(n,i). - Ridouane Oudra, Jul 26 2022

a(n) = Sum_{d|n} A006218(d). - Ridouane Oudra, Jul 27 2022

EXAMPLE

a(4) = 12 = sum of row 4 terms of triangle A143355: (7, + 3 + 1 + 1).

a(4) = 12 = (1, 1, 0, 1) dot (1, 3, 5, 8) = (1 + 3 + 0 + 8), where (1, 1, 0, 1) = row 4 of A051731 and A006218 = (1, 3, 5, 8, 10, 14,...).