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A030677 a(n) is the square root of A030676(n). 2

%I #8 Aug 12 2018 16:13:18

%S 4,5,6,7,23,8,27,9,30,34,15,58,21,235,257,88,94,315,318,334,110,362,

%T 119,123,127,131,426,438,45,461,149,482,492,159,162,165,168,171,551,

%U 56,569,1825,586,188,603,611,619,627,201,644,206,659,667,674,2155

%N a(n) is the square root of A030676(n).

%H Robert Israel, <a href="/A030677/b030677.txt">Table of n, a(n) for n = 1..10000</a>

%p revdigs:= proc(n)

%p local L, nL, i;

%p L:= convert(n, base, 10);

%p add(L[-i]*10^(i-1), i=1..nops(L));

%p end:

%p g:= proc(d) local m,x,y;

%p if d::even then

%p m:= d/2;

%p seq(x*10^m+revdigs(x),x=10^(m-1)..10^m-1)

%p else

%p m:= (d-1)/2;

%p seq(seq(x*10^(m+1)+y*10^m+revdigs(x),y=0..9),x=10^(m-1)..10^m-1)

%p fi

%p end proc:

%p g(1):= $1..9:

%p f:= proc(x) local d,y;

%p for d from 1 do

%p y:= ceil(sqrt(x*10^d));

%p if y^2 < (x+1)*10^d then return y fi

%p od;

%p end proc:

%p map(f, [g(1),g(2),g(3),g(4)]); # _Robert Israel_, Aug 12 2018

%Y Cf. A030676.

%K nonn,base

%O 1,1

%A _Patrick De Geest_

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Last modified March 28 05:39 EDT 2024. Contains 371235 sequences. (Running on oeis4.)