A143356 A051731 * A006218.

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

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,...).

Prog

(PARI) row(n) = my(d=divisors(n)); vector(n, k, #select(x->(x>=k), d)); \\ A135539
a(n) = my(v=row(n)); sum(i=1, n, numdiv(i)*v[i]); \\ Michel Marcus, Jul 26 2022

Crossrefs

Cf. A006218, A051731, A143355.

Cf. A135539.

Sequence in context: A365648 A374778 A038040 * A058270 A332934 A058199

Adjacent sequences: A143353 A143354 A143355 * A143357 A143358 A143359

Keyword

nonn

Author

Gary W. Adamson, Aug 10 2008

Extensions

Corrected typo in A-number in formula; added more terms - R. J. Mathar, Jan 19 2009

Status

approved