The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A007937 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A007937

Nonsquares such that some permutation of digits is a square.
(history; published version)

#18 by Bruno Berselli at Mon Oct 18 11:19:41 EDT 2021

STATUS

reviewed

approved

#17 by Joerg Arndt at Mon Oct 18 08:39:09 EDT 2021

STATUS

proposed

reviewed

#16 by Michel Marcus at Mon Oct 18 05:49:34 EDT 2021

STATUS

editing

proposed

#15 by Michel Marcus at Mon Oct 18 05:49:24 EDT 2021

CROSSREFS

Cf. A096600, A000290, A062892, A096600.

STATUS

proposed

editing

#14 by Michael S. Branicky at Mon Oct 18 05:41:31 EDT 2021

STATUS

editing

proposed

#13 by Michael S. Branicky at Mon Oct 18 05:41:04 EDT 2021

COMMENTS

A062892(a(n))>0.

FORMULA

A062892(a(n)) > 0.

PROG

(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

CROSSREFS

Cf. A096600, A000290, A062892.

STATUS

approved

editing

#12 by Harvey P. Dale at Mon Aug 17 14:32:29 EDT 2020

STATUS

editing

approved

#11 by Harvey P. Dale at Mon Aug 17 14:32:26 EDT 2020

LINKS

Harvey P. Dale, <a href="/A007937/b007937.txt">Table of n, a(n) for n = 1..2500</a>

STATUS

approved

editing

#10 by Harvey P. Dale at Mon Aug 17 14:31:01 EDT 2020

STATUS

editing

approved

#9 by Harvey P. Dale at Mon Aug 17 14:30:59 EDT 2020

MATHEMATICA

Select[Range[600], !IntegerQ[Sqrt[#]]&&AnyTrue[FromDigits/@ Permutations[ IntegerDigits[ #]], IntegerQ[ Sqrt[#]]&]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Aug 17 2020 *)

STATUS

approved

editing