The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A332919 a(n) is the sum of the sums of squared digits of all n-digit numbers. 2
 285, 5415, 79800, 1054500, 13110000, 156750000, 1824000000, 20805000000, 233700000000, 2593500000000, 28500000000000, 310650000000000, 3363000000000000, 36195000000000000, 387600000000000000, 4132500000000000000, 43890000000000000000, 464550000000000000000, 4902000000000000000000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Colin Barker, Table of n, a(n) for n = 1..950 Index entries for linear recurrences with constant coefficients, signature (20,-100). FORMULA a(n) = Sum_{k=10^(n-1)..10^n-1} A003132(k). From Colin Barker, Mar 06 2020: (Start) G.f.: 285*x*(1 - x) / (1 - 10*x)^2. a(n) = 20*a(n-1) - 100*a(n-2) for n > 2. a(n) = 57*2^(n-2) * 5^(n-1) * (1+9*n). (End) E.g.f.: (57/20)*(exp(10*x)*(1 + 90*x) - 1). - Stefano Spezia, Mar 06 2020 EXAMPLE a(1) = Sum_{k=1..9} k^2 = A000330(9) = 285. PROG (PARI) for(d=1, 8, print1(sum(k=10^(d-1), 10^d-1, digits(k)*digits(k)~), ", ")) (PARI) Vec(285*x*(1 - x) / (1 - 10*x)^2 + O(x^40)) \\ Colin Barker, Mar 06 2020 CROSSREFS Cf. A003132, A333034. Sequence in context: A209311 A176712 A225881 * A278629 A241970 A231422 Adjacent sequences: A332916 A332917 A332918 * A332920 A332921 A332922 KEYWORD nonn,base,easy AUTHOR Hugo Pfoertner, Mar 06 2020 EXTENSIONS More terms from Colin Barker, Mar 06 2020 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified May 28 04:05 EDT 2023. Contains 362992 sequences. (Running on oeis4.)