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A283237 a(n) = sigma_2(3*n). 3
10, 50, 91, 210, 260, 455, 500, 850, 820, 1300, 1220, 1911, 1700, 2500, 2366, 3410, 2900, 4100, 3620, 5460, 4550, 6100, 5300, 7735, 6510, 8500, 7381, 10500, 8420, 11830, 9620, 13650, 11102, 14500, 13000, 17220, 13700, 18100, 15470, 22100, 16820, 22750, 18500 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
a(n) = A001157(3*n).
Sum_{k=1..n} a(k) ~ (29*zeta(3)/9) * n^3. - Amiram Eldar, Dec 12 2023
MATHEMATICA
Table[DivisorSigma[2, 3n], {n, 1, 43}] (* Indranil Ghosh, Mar 03 2017 *)
PROG
(PARI) a(n) = sigma(3*n, 2); \\ Indranil Ghosh, Mar 03 2017
CROSSREFS
Sigma_2(k*n): A001157 (k=1), A099979 (k=2), this sequence (k=3).
Cf. A002117.
Sequence in context: A222633 A061861 A243226 * A036786 A085444 A102915
KEYWORD
nonn,easy
AUTHOR
Seiichi Manyama, Mar 03 2017
STATUS
approved

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Last modified July 19 00:30 EDT 2024. Contains 374388 sequences. (Running on oeis4.)