OFFSET
1,2
COMMENTS
The sequence of cubes starts: 1, 216, 512, 12167, 85184, 91125, 1061208, 1191016, ...
LINKS
Lars Blomberg, Table of n, a(n) for n = 1..10000
Jeremy Gardiner, Middle digit in cube numbers, Seqfan Mailing list, Dec 12 2016.
EXAMPLE
1^3 = (1), 114^3 = 148(1)544, 560^3 = 1756(1)6000
MATHEMATICA
a[n_]:=Part[IntegerDigits[n], (Length[IntegerDigits[n]] + 1)/2];
Select[Range[0, 771], OddQ[Length[IntegerDigits[#^3]]] && a[#^3]==1 &] (* Indranil Ghosh, Mar 06 2017 *)
PROG
(PARI)
isok(k) = my(d=digits(k^3)); (#d%2 == 1) && (d[#d\2 +1] == 1);
for(k=0, 771, if(isok(k)==1, print1(k, ", "))); \\ Indranil Ghosh, Mar 06 2017
(Python)
i=0
j=1
while i<=771:
n=str(i**3)
l=len(n)
if l%2 and n[(l-1)//2]=="1":
print(str(i), end=', ')
j+=1
i+=1 # Indranil Ghosh, Mar 06 2017
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Lars Blomberg, Jan 07 2017
STATUS
approved