Show the (decimal) value of a number of 1s appended with a 3, then squared

Show the (decimal) value of a number of 1s appended with a 3, then squared is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

Task

a(n) = (n 1's followed by a 3)^2, where 0 <= n < 8

Factor

a(n) = ((10ⁿ⁺¹ - 1) / 9 + 2)²

Works with: Factor version 0.99 2021-02-05

<lang factor>USING: io kernel math math.functions prettyprint ;

a ( n -- e m ) 1 + 10^ 1 - 9 / 2 + dup sq ;

8 [ a swap pprint bl . ] each-integer</lang>

Output:

3 9
13 169
113 12769
1113 1238769
11113 123498769
111113 12346098769
1111113 1234572098769
11111113 123456832098769

Ring

<lang ring> load "stdlib.ring"

decimals(0)

see "working..." + nl

row = 0 limit = 8

str = "3" for n = 1 to limit

   if n = 1
      strn = number(str) 
      res = pow(strn,2)
      see "{" + strn + "," + res + "}" + nl
   else
      str = "1" + strn
      strn = number(str) 
      res = pow(strn,2)
      see "{" + strn + "," + res + "}" + nl
   ok   

next

see "done..." + nl </lang>

Output:

working...
{3,9}
{13,169}
{113,12769}
{1113,1238769}
{11113,123498769}
{111113,12346098769}
{1111113,1234572098769}
{11111113,123456832098769}
done...