OFFSET
1,2
EXAMPLE
a(2)=7 because sum of digits of square of 2 is 4 and sum of digits of square of 4 is 1+6=7
MATHEMATICA
Array[Total[IntegerDigits[(Total[IntegerDigits[#^2]])^2]]&, 90] (* Harvey P. Dale, Jan 17 2012 *)
Table[Nest[Total[IntegerDigits[#^2]]&, n, 2], {n, 90}] (* Harvey P. Dale, Mar 07 2018 *)
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Henry Bottomley, Jun 19 2000
STATUS
approved