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A030679
Cube root of A030678.
2
5, 3, 7, 16, 8, 4, 9, 20, 21, 48, 61, 15, 164, 82, 188, 92, 96, 215, 466, 481, 23, 236, 242, 533, 253, 258, 122, 576, 587, 277, 606, 615, 624, 632, 64, 301, 656, 143, 312, 679, 1479, 322, 70, 707, 714, 72, 1565, 34, 1593, 346, 1619, 1632, 763, 357, 1668
OFFSET
1,1
LINKS
FORMULA
a(n) = A030669(A002113(n+1)) = A030678(n)^(1/3). - Robert Israel, Dec 25 2018
MAPLE
N:= 3: # to get extensions of all palindromes of <= N digits
f:= proc(n) local d, x;
for d from 1 do
x:= ceil((n*10^d)^(1/3));
if x^3 < (n+1)*10^d then return x fi
od
end proc:
digrev:= proc(n) local i, L;
L:= convert(n, base, 10);
add(L[-i]*10^(i-1), i=1..nops(L))
end proc:
Res:= seq(f(i), i=1..9):
for d from 2 to N do
if d::even then
m:= d/2;
Res:= Res, seq(f(n*10^m + digrev(n)), n=10^(m-1)..10^m-1);
else
m:= (d-1)/2;
Res:= Res, seq(seq(f(n*10^(m+1)+y*10^m+digrev(n)), y=0..9), n=10^(m-1)..10^m-1)
fi
od: Res; # Robert Israel, Dec 25 2018
CROSSREFS
KEYWORD
nonn,base
STATUS
approved