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.

A064121 Nonprime numbers n such that the sum of aliquot divisors of n (A001065) and product of aliquot divisors of n (A048741) are both perfect squares.

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%I A064121 #10 Jan 07 2020 09:07:05
%S A064121 1,12,75,76,124,147,153,176,243,332,363,477,507,524,575,688,867,892,
%T A064121 963,1075,1083,1421,1532,1573,1587,1611,1916,2032,2075,2224,2299,2401,
%U A064121 2421,2523,2572,2883,2891,3100,3479,3776,3888,4107,4336,4527,4961,4975
%N A064121 Nonprime numbers n such that the sum of aliquot divisors of n (A001065) and product of aliquot divisors of n (A048741) are both perfect squares.
%H A064121 Amiram Eldar, <a href="/A064121/b064121.txt">Table of n, a(n) for n = 1..10000</a>
%t A064121 Select[ Range[5000], IntegerQ[ Sqrt[ Apply[ Plus, Delete[ Divisors[ # ], -1]]]] && IntegerQ[ Sqrt[ Apply[ Times, Delete[Divisors[ # ], -1]]]] && ! PrimeQ[ # ] & ]
%Y A064121 Variant of A064116. - _R. J. Mathar_, Oct 02 2008
%Y A064121 Cf. A064710.
%K A064121 easy,nonn
%O A064121 1,2
%A A064121 _Robert G. Wilson v_, Oct 14 2001