login
Powers of 4 written backwards.
4

%I #10 Apr 09 2015 11:12:56

%S 1,4,61,46,652,4201,6904,48361,63556,441262,6758401,4034914,61277761,

%T 46880176,654534862,4281473701,6927694924,48196897171,63767491786,

%U 449609778472,6777261159901,4011156408934,61444068129571

%N Powers of 4 written backwards.

%H Alois P. Heinz, <a href="/A071582/b071582.txt">Table of n, a(n) for n = 0..1000</a>

%p a:= n-> (s-> parse(cat(s[-i]$i=1..length(s))))(""||(4^n)):

%p seq(a(n), n=0..50); # _Alois P. Heinz_, Apr 09 2015

%t FromDigits[Reverse[IntegerDigits[#]]]&/@(4^Range[0,30]) (* _Harvey P. Dale_, Jan 28 2013 *)

%o (PARI) for(i=1,50,n=4^i; s=ceil(log(n)/log(10)); print1(sum(i=0,s,10^(s-i-1)*(floor(n/10^i)-10*floor(n/10^(i+1)))),","))

%K easy,nonn,base

%O 0,2

%A _Benoit Cloitre_, Jun 01 2002