A183227 a(n) is the base-5 digit sum of 10^n-1.

0, 5, 11, 15, 19, 23, 31, 31, 35, 43, 51, 55, 59, 63, 63, 71, 79, 87, 91, 95, 95, 95, 107, 115, 123, 119, 135, 139, 135, 147, 159, 163, 159, 155, 163, 171, 175, 187, 179, 191, 195, 203, 211, 211, 211, 219, 219, 231, 235, 239

Offset: 0

Author

Washington Bomfim, Jan 01 2011

Keywords

• nonn
• easy
• base

Examples

			a(9) = 43 because 10^9 - 1 is written as 4021444444444_5, and 2^9 - 1 = 511 is written as 4021_5.
		

Crossrefs

Cf. A183226, A183228.

Programs

Maple

A053824 := proc(n) add(d,d=convert(n,base,5)) ; end proc:
A183227 := proc(n) A053824(10^n-1) ; end proc: # R. J. Mathar, Jan 09 2011

PARI

\\L is a list of the N digits of 2^n - 1 in  quinary
convert(n)={n = 2^n - 1; 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};
print1("0, "); for(n = 1,100, convert(n); s = 0; for(i = 1, N, s += L[i];); print1(s+4*n, ", "));

Formula

a(n) = A053824(10^n-1) = 4*n + A053824(2^n-1).