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A183226 Sum of digits of (2^n) in base 5, also sum of digits of (10^n) in base 5. 3
1, 2, 4, 4, 4, 4, 8, 4, 4, 8, 12, 12, 12, 12, 8, 12, 16, 20, 20, 20, 16, 12, 20, 24, 28, 20, 32, 32, 24, 32, 40, 40, 32, 24, 28, 32, 32, 40, 28, 36, 36, 40, 44, 40, 36, 40, 36, 44, 44, 44, 44, 48, 52, 52, 48, 56, 40, 56, 68, 60, 52, 52, 48, 60, 56, 64, 60, 48, 56, 60, 60, 64, 60, 60, 60, 64, 52, 48, 64, 68, 56, 80, 80 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

If i >= 2, a(n) mod 4 = 0. (Cf. A053824)

LINKS

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

EXAMPLE

a(9) = 8 because 10^9 = 4022000000000_5, and 2^9 = 512 = 4022_5.

MAPLE

a:= n-> add(i, i=convert (2^n, base, 5)):

seq(a(n), n=0..82);  # Alois P. Heinz, Jan 06 2011

MATHEMATICA

Table[Plus@@IntegerDigits[2^n, 5], {n, 0, 49}] (* Either that one or this one *) Table[Plus@@IntegerDigits[10^n, 5], {n, 0, 49}] (* Alonso del Arte, Jan 06 2011 *)

PROG

(PARI)\\  L is the list of the N digits of 2^n in quinary.

     \\ L[1] = a_0 , ..., L[N] = a_(N-1).

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); an=0; for(i=1, N, an+=L[i]; ); print1(an, ", "));

(PARI) t(n) = if(n<1, 0, if(n%5, t(n-1)+1, t(n/5)));

vector(200, n, n--; t(2^n)) \\ Altug Alkan, Oct 28 2015

CROSSREFS

Cf. A055476, A173670, A183227, A183228.

Sequence in context: A194443 A220523 A220527 * A235863 A220495 A194441

Adjacent sequences:  A183223 A183224 A183225 * A183227 A183228 A183229

KEYWORD

nonn,easy,base

AUTHOR

Washington Bomfim, Jan 01 2011

STATUS

approved

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Last modified December 3 18:47 EST 2016. Contains 278745 sequences.