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.

Showing 1-5 of 5 results.

A096599 Squares k^2 with property that A062892(k^2) = 1.

Original entry on oeis.org

0, 1, 4, 9, 16, 25, 36, 49, 64, 81, 121, 225, 289, 324, 361, 484, 529, 576, 676, 729, 784, 841, 1156, 1225, 1444, 1521, 1681, 1849, 2116, 2209, 2601, 2704, 3025, 3136, 3249, 3364, 3481, 3721, 3844, 3969, 4225, 4356, 4489, 4624, 5041, 5184, 5329, 5476
Offset: 1

Views

Author

Reinhard Zumkeller, Jun 29 2004

Keywords

Crossrefs

Programs

  • Python
    from math import isqrt
    from sympy.utilities.iterables import multiset_permutations as mp
    def sqr(n): return isqrt(n)**2 == n
    def ok(square):
        s = str(square)
        perms = (int("".join(p)) for p in mp(s, len(s)))
        return len(set(p for p in perms if sqr(p))) == 1
    def aupto(limit): return [k*k for k in range(isqrt(limit)+1) if ok(k*k)]
    print(aupto(5476)) # Michael S. Branicky, Oct 18 2021

Extensions

Definition clarified by N. J. A. Sloane, Jan 16 2014

A068805 Suppose the integer m has k decimal digits; make a list of the k! strings obtained by permuting the digits in all possible ways; discard any leading zeros; count distinct squares in the list (A062892); a(n) = smallest m that yields n squares.

Original entry on oeis.org

1, 100, 169, 10269, 13468, 10044, 100269, 1000269, 10069, 100069, 1001466, 1000044, 10012689, 10045669, 10001466, 1003468, 10023469, 1000069, 10000069, 10002456, 10003468, 100045669, 100023469, 100001466, 100124469, 100045678, 100345689, 100023489, 100000069, 100002456
Offset: 1

Views

Author

Amarnath Murthy, Mar 06 2002

Keywords

Examples

			a(3) = 169 whose 3 permutations 169, 196 and 961 yield three different squares.
		

Crossrefs

Programs

  • Mathematica
    a=Table[0, {15}]; Do[b=Count[ IntegerQ /@ Sqrt[ FromDigits /@ Permutations[ IntegerDigits[n]]], True]; If[b<15&&a[[b]]==0, a[[b]]=n], {n, 1, 287618} ] (* Robert G. Wilson v, May 22 2003 *)

Extensions

More terms from Robert G. Wilson v, May 22 2003
a(13)-a(20) from John W. Layman, Sep 27 2004
More terms from David A. Corneth, Oct 18 2021

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

A096600 Numbers such that in decimal representation all permutations of digits are nonsquares.

Original entry on oeis.org

2, 3, 5, 6, 7, 8, 11, 12, 13, 14, 15, 17, 19, 20, 21, 22, 23, 24, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 37, 38, 39, 41, 42, 43, 44, 45, 47, 48, 50, 51, 53, 54, 55, 56, 57, 58, 59, 60, 62, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 82, 83, 84, 85, 86, 87
Offset: 1

Views

Author

Reinhard Zumkeller, Jun 29 2004

Keywords

Comments

A062892(a(n)) = 0.

Examples

			134=2*67, 143=11*13, 314=2*157, 341=11*31, 413=7*59 and 431=A000040(83), therefore 134, 143, 314, 341, 413 and 431 are terms.
		

Crossrefs

Programs

  • Mathematica
    Select[Range[100],NoneTrue[Sqrt[#]&/@(FromDigits/@Permutations[IntegerDigits[ #]]),IntegerQ]&] (* Harvey P. Dale, Dec 04 2022 *)

A096598 Squares such that some permutation of digits is also a square (in decimal representation).

Original entry on oeis.org

100, 144, 169, 196, 256, 400, 441, 625, 900, 961, 1024, 1089, 1296, 1369, 1600, 1764, 1936, 2025, 2304, 2401, 2500, 2809, 2916, 3600, 4096, 4761, 4900, 6400, 7056, 8100, 9025, 9216, 9604, 9801, 10000, 10201, 10404, 10609, 10816, 11025
Offset: 1

Views

Author

Reinhard Zumkeller, Jun 29 2004

Keywords

Comments

A062892(a(n)) > 1.

Examples

			1024 = 32^2 and also 2401=49^2, therefore 1024 (and 2401) is a term.
		

Crossrefs

Showing 1-5 of 5 results.