cp's OEIS Frontend

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

%I A183228 #17 Sep 20 2019 09:00:08
%S A183228 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,
%T A183228 33,33,25,33,41,41,33,25,29,33,33,41,29,37,37,41,45,41,37,41,37,45,45,
%U A183228 45,45,49,53,53,49,57,41,57,69
%N A183228 a(n) is the base-5 digit sum of 10^n+1.
%H A183228 Robert Israel, <a href="/A183228/b183228.txt">Table of n, a(n) for n = 0..10000</a>
%F A183228 a(n) = A053824(10^n+1) = 1 + A053824(2^n).
%e A183228 a(9) = 9 because 10^9 + 1 is written as 4022000000001_5, and 2^9 = 512 is written as 4022_5.
%p A183228 A053824 := proc(n) add(d,d=convert(n,base,5)) ; end proc:
%p A183228 A183228 := proc(n) A053824(10^n+1) ; end proc: # _R. J. Mathar_, Jan 09 2011
%t A183228 Table[Total[IntegerDigits[10^n+1,5]],{n,0,60}] (* _Harvey P. Dale_, Jun 10 2018 *)
%o A183228 (PARI)\\ L is the list of the N digits of 2^n in quinary.
%o A183228 convert(n)={ n = 2^n; x = n; N = floor(log(n)/log(5))+1;
%o A183228 L = listcreate(N);
%o A183228 while(x, n=floor(n/5); r= x-5*n; listput(L, r); x = n; );
%o A183228 L; N};
%o A183228 for(n=0,100,convert(n); s=0;for(i=1,N, s+=L[i];); print1(s+1,", "));
%o A183228 (PARI) a(n) = sumdigits(10^n+1, 5); \\ _Michel Marcus_, Sep 20 2019
%Y A183228 Cf. A183226, A183227.
%K A183228 nonn,easy,base
%O A183228 0,1
%A A183228 _Washington Bomfim_, Jan 02 2011
%E A183228 Formula corrected by _Robert Israel_, Sep 19 2019