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A030677
a(n) is the square root of A030676(n).
2
4, 5, 6, 7, 23, 8, 27, 9, 30, 34, 15, 58, 21, 235, 257, 88, 94, 315, 318, 334, 110, 362, 119, 123, 127, 131, 426, 438, 45, 461, 149, 482, 492, 159, 162, 165, 168, 171, 551, 56, 569, 1825, 586, 188, 603, 611, 619, 627, 201, 644, 206, 659, 667, 674, 2155
OFFSET
1,1
LINKS
MAPLE
revdigs:= proc(n)
local L, nL, i;
L:= convert(n, base, 10);
add(L[-i]*10^(i-1), i=1..nops(L));
end:
g:= proc(d) local m, x, y;
if d::even then
m:= d/2;
seq(x*10^m+revdigs(x), x=10^(m-1)..10^m-1)
else
m:= (d-1)/2;
seq(seq(x*10^(m+1)+y*10^m+revdigs(x), y=0..9), x=10^(m-1)..10^m-1)
fi
end proc:
g(1):= $1..9:
f:= proc(x) local d, y;
for d from 1 do
y:= ceil(sqrt(x*10^d));
if y^2 < (x+1)*10^d then return y fi
od;
end proc:
map(f, [g(1), g(2), g(3), g(4)]); # Robert Israel, Aug 12 2018
CROSSREFS
Cf. A030676.
Sequence in context: A107759 A161627 A030667 * A071177 A010754 A187807
KEYWORD
nonn,base
STATUS
approved