A362505 Nonnegative numbers of the form x*y where x and y have the same set of decimal digits.
0, 1, 4, 9, 11, 16, 25, 36, 44, 49, 64, 81, 99, 100, 111, 121, 144, 169, 176, 196, 225, 252, 256, 275, 289, 324, 361, 396, 400, 403, 441, 444, 484, 529, 539, 574, 576, 625, 676, 704, 729, 736, 765, 784, 841, 891, 900, 961, 976, 999, 1000, 1008, 1010, 1024
Offset: 1
Examples
The first terms, alongside an appropriate factorization, are: n a(n) x y -- ---- -- --- 1 0 0 0 2 1 1 1 3 4 2 2 4 9 3 3 5 11 1 11 6 16 4 4 7 25 5 5 8 36 6 6 9 44 2 22 10 49 7 7 11 64 8 8 12 81 9 9 13 99 3 33 14 100 10 10 15 111 1 111
Programs
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PARI
is(n) = { if (n==0, 1, fordiv (n, x, if (Set(digits(x))==Set(digits(n/x)), return (1))); return (0)); } -
Python
from sympy import divisors def ok(n): return n == 0 or any(set(str(x)) == set(str(n//x)) for x in divisors(n)) print([k for k in range(1025) if ok(k)]) # Michael S. Branicky, Apr 23 2023
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