cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A007937 Nonsquares such that some permutation of digits is a square.

Original entry on oeis.org

10, 18, 40, 46, 52, 61, 63, 90, 94, 106, 108, 112, 136, 148, 160, 163, 180, 184, 205, 211, 234, 243, 250, 252, 259, 265, 279, 295, 297, 298, 306, 316, 342, 360, 406, 409, 414, 418, 423, 432, 448, 460, 478, 481, 487, 490, 502, 520, 522, 526, 562, 567, 592
Offset: 1

Views

Author

R. Muller

Keywords

Crossrefs

Programs

  • Mathematica
    Select[Range[600],!IntegerQ[Sqrt[#]]&&AnyTrue[FromDigits/@ Permutations[ IntegerDigits[ #]],IntegerQ[ Sqrt[#]]&]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Aug 17 2020 *)
  • Python
    from math import isqrt
    from sympy.utilities.iterables import multiset_permutations as mp
    def sqr(n): return isqrt(n)**2 == n
    def ok(n):
        if sqr(n): return False
        s = str(n)
        return any(sqr(int("".join(p))) for p in mp(s, len(s)))
    print([k for k in range(600) if ok(k)]) # Michael S. Branicky, Oct 18 2021

Formula

A062892(a(n)) > 0.

Extensions

More terms from Reinhard Zumkeller, Jun 29 2004