A231668 a(n) = Sum_{i=0..n} digsum_5(i), where digsum_5(i) = A053824(i).

0, 1, 3, 6, 10, 11, 13, 16, 20, 25, 27, 30, 34, 39, 45, 48, 52, 57, 63, 70, 74, 79, 85, 92, 100, 101, 103, 106, 110, 115, 117, 120, 124, 129, 135, 138, 142, 147, 153, 160, 164, 169, 175, 182, 190, 195, 201, 208, 216, 225, 227, 230, 234, 239, 245, 248, 252, 257, 263, 270, 274, 279, 285, 292, 300, 305, 311, 318, 326, 335, 341, 348, 356, 365, 375, 378, 382, 387, 393, 400

Offset: 0

Author

N. J. A. Sloane, Nov 13 2013

Keywords

• nonn
• base

References

• Jean-Paul Allouche and Jeffrey Shallit, Automatic sequences, Cambridge University Press, 2003, p. 94.

Links

• Amiram Eldar, Table of n, a(n) for n = 0..10000
• Jean Coquet, Power sums of digital sums, J. Number Theory, Vol. 22, No. 2 (1986), pp. 161-176.
• P. J. Grabner, P. Kirschenhofer, H. Prodinger and R. F. Tichy, On the moments of the sum-of-digits function, PDF, Applications of Fibonacci numbers, Vol. 5 (St. Andrews, 1992), pp. 263-271, Kluwer Acad. Publ., Dordrecht, 1993.
• Hsien-Kuei Hwang, Svante Janson and Tsung-Hsi Tsai, Exact and Asymptotic Solutions of a Divide-and-Conquer Recurrence Dividing at Half: Theory and Applications, ACM Transactions on Algorithms, Vol. 13, No. 4 (2017), Article #47; ResearchGate link; preprint, 2016.
• J.-L. Mauclaire and Leo Murata, On q-additive functions. I, Proc. Japan Acad. Ser. A Math. Sci., Vol. 59, No. 6 (1983), pp. 274-276.
• J.-L. Mauclaire and Leo Murata, On q-additive functions. II, Proc. Japan Acad. Ser. A Math. Sci., Vol. 59, No. 9 (1983), pp. 441-444.
• J. R. Trollope, An explicit expression for binary digital sums, Math. Mag., Vol. 41, No. 1 (1968), pp. 21-25.

Crossrefs

Cf. A053824, A231669, A231670, A231671.

Programs

Mathematica

a[n_] := Plus @@ IntegerDigits[n, 5]; Accumulate @ Array[a, 80, 0] (* Amiram Eldar, Dec 09 2021 *)

PARI

a(n) = sum(i=0, n, sumdigits(i, 5)); \\ Michel Marcus, Sep 20 2017

Formula

a(n) ~ 2*n*log(n)/log(5). - Amiram Eldar, Dec 09 2021