A037123 a(n) = a(n-1) + sum of digits of n.

0, 1, 3, 6, 10, 15, 21, 28, 36, 45, 46, 48, 51, 55, 60, 66, 73, 81, 90, 100, 102, 105, 109, 114, 120, 127, 135, 144, 154, 165, 168, 172, 177, 183, 190, 198, 207, 217, 228, 240, 244, 249, 255, 262, 270, 279, 289, 300, 312, 325, 330, 336, 343, 351, 360, 370, 381

Offset

0,3

Comments

Sum of digits of A007908(n). - Franz Vrabec, Oct 22 2007

Also digital sum of A138793(n) for n > 0. - Bruno Berselli, May 27 2011

Sum of the digital sum of i for i from 0 to n. - N. J. A. Sloane, Nov 13 2013

References

N. Agronomof, Sobre una función numérica, Revista Mat. Hispano-Americana 1 (1926), 267-269.

Maurice d'Ocagne, Sur certaines sommations arithmétiques, J. Sciencias Mathematicas e Astronomicas 7 (1886), 117-128.

Links

David A Corneth, Table of n, a(n) for n = 0..10008

P.-H. Cheo and S.-C. Yien, A problem on the k-adic representation of positive integers, Acta Math. Sinica 5, 433-438 (1955).

J. Coquet, Power sums of digital sums, J. Number Theory 22 (1986), no. 2, 161-176.

H. Delange, Sur la fonction sommatoire de la fonction "somme des chiffres", Enseignement Math. (2) 21 (1975), 31-47.

P. J. Grabner, P. Kirschenhofer, H. Prodinger and R. F. Tichy, On the moments of the sum-of-digits function, Applications of Fibonacci numbers, Vol. 5 (St. Andrews, 1992), Kluwer Acad. Publ., Dordrecht, 1993, 263-271.

Hsien-Kuei Hwang, S. Janson, and T.-H. Tsai, Exact and asymptotic solutions of the recurrence f(n) = f(floor(n/2)) + f(ceiling(n/2)) + g(n): theory and applications, Preprint 2016.

Hsien-Kuei Hwang, S. Janson, and T.-H. Tsai, Exact and Asymptotic Solutions of a Divide-and-Conquer Recurrence Dividing at Half: Theory and Applications, ACM Transactions on Algorithms, 13:4 (2017), #47; DOI: 10.1145/3127585.

J.-L. Mauclaire and Leo Murata, On q-additive functions, I. Proc. Japan Acad. Ser. A Math. Sci. 59 (1983), no. 6, 274-276.

J.-L. Mauclaire and Leo Murata, On q-additive functions, II. Proc. Japan Acad. Ser. A Math. Sci. 59 (1983), no. 9, 441-444.

H. Riede, Asymptotic estimation of a sum of digits, Fibonacci Q. 36, No. 1, 72-75 (1998).

J. R. Trollope, An explicit expression for binary digital sums, Math. Mag. 41 1968 21-25.

Formula

a(n) = Sum_{k=0..n} s(k) = Sum_{k=0..n} A007953(k), where s(k) denote the sum of the digits of k in decimal representation. Asymptotic expression: a(n-1) = Sum_{k=0..n-1} s(k) = 4.5*n*log_10(n) + O(n). - Antonio G. Astudillo (afg_astudillo(AT)hotmail.com), Sep 07 2002

a(n) = n*(n+1)/2 - 9*Sum_{k=1..n} Sum_{i=1..ceiling(log_10(k))} floor(k/10^i). - Benoit Cloitre, Aug 28 2003

From Hieronymus Fischer, Jul 11 2007: (Start)

G.f.: Sum_{k>=1} ((x^k - x^(k+10^k) - 9x^(10^k))/(1-x^(10^k)))/(1-x)^2.

a(n) = (1/2)*((n+1)*(n - 18*Sum_{k>=1} floor(n/10^k)) + 9*Sum_{k>=1} (1 + floor(n/10^k))*floor(n/10^k)*10^k).

a(n) = (1/2)*((n+1)*(2*A007953(n)-n) + 9*Sum_{k>=1} (1+floor(n/10^k))*floor(n/10^k)*10^k). (End)

a(n) = A007953(A053064(n)). - Reinhard Zumkeller, Oct 10 2008

From Wojciech Raszka, Jun 14 2019: (Start)

a(10^k - 1) = 10*a(10^(k - 1) - 1) + 45*10^(k - 1) for k > 0.

a(n) = a(n mod m) + MSD*a(m - 1) + (MSD*(MSD - 1)/2)*m + MSD*((n mod m) + 1), where m = 10^(A055642(n) - 1), MSD = A000030(n). (End)

Maple

# From N. J. A. Sloane, Nov 13 2013:
digsum:=proc(n, B) local a; a := convert(n, base, B):
add(a[i], i=1..nops(a)): end;
f:=proc(n, k, B) global digsum; local i;
add( digsum(i, B)^k, i=0..n); end;
lprint([seq(digsum(n, 10), n=0..100)]); # A007953
lprint([seq(f(n, 1, 10), n=0..100)]); #A037123
lprint([seq(f(n, 2, 10), n=0..100)]); #A074784
lprint([seq(f(n, 3, 10), n=0..100)]); #A231688
lprint([seq(f(n, 4, 10), n=0..100)]); #A231689

Mathematica

Table[Plus@@Flatten[IntegerDigits[Range[n]]], {n, 0, 200}] (* Enrique Pérez Herrero, Oct 12 2015 *)
a[0] = 0; a[n_] := a[n - 1] + Plus @@ IntegerDigits@ n; Array[a, 70, 0] (* Robert G. Wilson v, Jul 06 2018 *)

Prog

(PARI) a(n)=n*(n+1)/2-9*sum(k=1, n, sum(i=1, ceil(log(k)/log(10)), floor(k/10^i)))
(PARI) a(n)={n++; my(t, i, s); c=n; while(c!=0, i++; c\=10); for(j=1, i, d=(n\10^(i-j))%10; t+=(10^(i-j)*(s*d+binomial(d, 2)+d*9*(i-j)/2)); s+=d); t} \\ David A. Corneth, Aug 16 2013
(Perl) for $i (0..100){ @j = split "", $i; for (@j){ $sum += $_; } print "$sum, "; } __END__ # gamo(AT)telecable.es
(Magma) [ n eq 0 select 0 else &+[&+Intseq(k): k in [0..n]]: n in [0..56] ];  // Bruno Berselli, May 27 2011

Crossrefs

Cf. A004207, A016052, A131383, A131384, A131451.

Cf. also A074784, A231688, A231689.

Partial sums of A007953.

Sequence in context: A054632 A109453 A217627 * A062918 A113168 A341192

Adjacent sequences: A037120 A037121 A037122 * A037124 A037125 A037126

Keyword

nonn,base,easy

Author

Vasiliy Danilov (danilovv(AT)usa.net), Jun 15 1998

Extensions

More terms from Antonio G. Astudillo (afg_astudillo(AT)hotmail.com), Sep 07 2002

Status

approved