OFFSET
1,3
COMMENTS
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..10000 (terms for n = 1..231 from R. J. Mathar)
Bernard Schott, The different ways
FORMULA
EXAMPLE
Zero ways: 169 = 13^2 cannot be equal to k * rev(k).
One way: 400 = 200 * 2; 10201 = 101 * 101; 162409 = 169 * 961.
Two ways: 7683984 = 2772 * 2772 = 1584 * 4851.
Three ways: 6350400 = 14400 * 441 = 25200 * 252 = 44100 * 144.
MAPLE
isA305231 := proc(n)
local d;
for d in numtheory[divisors](n) do
if d = digrev(n/d) then
return true ;
end if;
end do:
false ;
end proc:
n := 1;
for i from 0 to 4000 do
i2 := i^2 ;
if isA305231(i2) then
printf("%d %d\n", n, i2) ;
n := n+1 ;
end if;
end do: # R. J. Mathar, Aug 09 2019
MATHEMATICA
{0}~Join~Select[Range[10^3]^2, (d1=Select[Divisors[n=#], #<=Sqrt@n&]; Or@@Table[d1[[k]]==(IntegerReverse/@(n/d1))[[k]], {k, Length@d1}])&] (* Giorgos Kalogeropoulos, Jun 09 2021 *)
PROG
(Python)
from sympy import divisors
A325148_list = [0]
for n in range(10**6):
n2 = n**2
for m in divisors(n2):
if m > n:
break
if m == int(str(n2//m)[::-1]):
A325148_list.append(n2)
break # Chai Wah Wu, Jun 09 2021
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Bernard Schott, Apr 03 2019
EXTENSIONS
Definition corrected by N. J. A. Sloane, Aug 01 2019
STATUS
approved