OFFSET
0,3
COMMENTS
LINKS
Hans Havermann, Table of n, a(n) for n = 0..10000
E. Angelini, Sum of squares -- and a concatenation, SeqFan list, June 23, 2015.
EXAMPLE
10 may be sectioned into a single part, the (sum of the) square of which is 100. Because it is the smallest number to have a sum of 100, a(100) = 10.
101 may be sectioned into two parts, 10 and 1, the sum of the squares of which is 101. Because it is the smallest number to have a sum of 101, a(101) = 101.
3355 may be sectioned into 3, 35, and 5, the sum of the squares of which is 1259. Because it is the smallest number to have a sum of 1259, a(1259) = 3355.
MATHEMATICA
a[0]=0; a[n_] := Min[ FromDigits/@ Flatten/@ IntegerDigits@ Flatten[ Permutations/@ Sqrt[ IntegerPartitions[ n, {1, 5}, Range[ Sqrt@ n]^2 ]], 1]]; a/@ Range[0, 99] (* Giovanni Resta, Jun 26 2015 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Hans Havermann, Jun 25 2015
STATUS
approved