cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A090580 Number of numbers with 5 decimal digits and sum of digits = n.

Original entry on oeis.org

1, 5, 15, 35, 70, 126, 210, 330, 495, 714, 992, 1330, 1725, 2170, 2654, 3162, 3675, 4170, 4620, 4998, 5283, 5460, 5520, 5460, 5283, 4998, 4620, 4170, 3675, 3162, 2654, 2170, 1725, 1330, 992, 714, 495, 330, 210, 126, 70, 35, 15, 5, 1
Offset: 1

Views

Author

Hugo Pfoertner, Jan 12 2004

Keywords

Comments

There are 90000 numbers with 5 decimal digits, the smallest being 10000 and the largest 99999.

Examples

			a(2)=5: 10001, 10010, 10100, 11000, 20000.
		

Crossrefs

Cf. A071817 3-digit numbers, A090579 4-digit numbers, A090581 6-digit numbers.

Programs

  • Mathematica
    Rest@ CoefficientList[Series[(x - x^10)/(1 - x) ((1 - x^10)/(1 - x))^4, {x, 0, 45}], x] (* or *)
    Function[w, Count[w, #] & /@ Range[Max@ w]]@ Map[Total@ IntegerDigits@ # &, Range[10^#, 10^(# + 1) - 1]] &@ 4 (* Michael De Vlieger, Dec 07 2016 *)
    Tally[Total[IntegerDigits[#]]&/@Range[10000,99999]][[All,2]] (* Harvey P. Dale, Jul 08 2019 *)
  • PARI
    b=vector(45,i,0);for(n=10000,99999,a=eval(Vec(Str(n)));b[sum(j=1,5,a[j])]++);for(n=1,45,print1(b[n],",")) - Herman Jamke (hermanjamke(AT)fastmail.fm), Oct 19 2006

Formula

G.f.: (x - x^10)/(1 - x)*((1 - x^10)/(1 - x))^4. - Michael De Vlieger, Dec 07 2016