A183228 a(n) is the base-5 digit sum of 10^n+1.

2, 3, 5, 5, 5, 5, 9, 5, 5, 9, 13, 13, 13, 13, 9, 13, 17, 21, 21, 21, 17, 13, 21, 25, 29, 21, 33, 33, 25, 33, 41, 41, 33, 25, 29, 33, 33, 41, 29, 37, 37, 41, 45, 41, 37, 41, 37, 45, 45, 45, 45, 49, 53, 53, 49, 57, 41, 57, 69

Offset: 0

Author

Washington Bomfim, Jan 02 2011

Keywords

• nonn
• easy
• base

Examples

			a(9) = 9 because 10^9 + 1 is written as 4022000000001_5, and 2^9 = 512 is written as 4022_5.
		

Links

• Robert Israel, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A183226, A183227.

Programs

Maple

A053824 := proc(n) add(d,d=convert(n,base,5)) ; end proc:
A183228 := proc(n) A053824(10^n+1) ; end proc: # R. J. Mathar, Jan 09 2011

Mathematica

Table[Total[IntegerDigits[10^n+1,5]],{n,0,60}] (* Harvey P. Dale, Jun 10 2018 *)

PARI

\\ L is the list of the N digits of 2^n in quinary.
convert(n)={ n = 2^n; x = n; N = floor(log(n)/log(5))+1;
L = listcreate(N);
while(x, n=floor(n/5); r= x-5*n; listput(L, r); x = n; );
L; N};
for(n=0,100,convert(n); s=0;for(i=1,N, s+=L[i];); print1(s+1,", "));

PARI

a(n) = sumdigits(10^n+1, 5); \\ Michel Marcus, Sep 20 2019

Formula

a(n) = A053824(10^n+1) = 1 + A053824(2^n).

Extensions

Formula corrected by Robert Israel, Sep 19 2019