A257763 Zeroless numbers n such that n and n^2 have the same set of decimal digits.
1, 4762, 4832, 12385, 14829, 26394, 34196, 36215, 49827, 68474, 72576, 74528, 79286, 79836, 94583, 94867, 96123, 98376, 123385, 123546, 124235, 124365, 124579, 124589, 125476, 125478, 126969, 129685, 135438, 139256, 139261, 139756, 149382, 152385, 156242
Offset: 1
Examples
4762 is in the sequence because it is zeroless and 4762^2 = 22676644 has the same set of decimal digits as 4762: {2,4,6,7}.
Links
- Alois P. Heinz, Table of n, a(n) for n = 1..10000
Programs
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Maple
a:= proc(n) option remember; local k, s; for k from 1+`if`(n=1, 0, a(n-1)) do s:= {convert(k, base, 10)[]}; if not 0 in s and s={convert(k^2, base, 10)[]} then return k fi od end: seq(a(n), n=1..10);
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Mathematica
sameQ[n_]:=Union[IntegerDigits[n]]==Union[IntegerDigits[n^2]];Select[Range@156242,And[FreeQ[IntegerDigits[#],0],sameQ[#]]&] (* Ivan N. Ianakiev, May 08 2015 *)
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PARI
isok(n) = vecmin(d=digits(n)) && Set(d) == Set(digits(n^2)); \\ Michel Marcus, May 31 2015
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Python
A257763_list = [n for n in range(1,10**6) if not '0' in str(n) and set(str(n)) == set(str(n**2))] # Chai Wah Wu, May 31 2015