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.

A236474 Numbers such that the sum of unitary divisors (A034448) is equal to the sum of exponential divisors (A051377).

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%I A236474 #24 Aug 19 2018 10:43:27
%S A236474 1,20,45,320,6615,382200,680890228200,8169778639360,27445575588992,
%T A236474 56626123593600,1235050901504640
%N A236474 Numbers such that the sum of unitary divisors (A034448) is equal to the sum of exponential divisors (A051377).
%C A236474 Following numbers also belongs to this sequence, however their actual positions are unknown: 3640527948039840, 181552482521182080, 19736989888296320640, 108455561012908979640, 796015410768776072160, 4220107447484548287360, 39697147230528075361920, 202868762331595335655680, 668431747385354202124160, 124402428235930297906738935, 2456687209744634987008753664.
%H A236474 Tim Trudgian, <a href="http://arxiv.org/abs/1312.4615">The sum of the unitary divisor function</a>, arXiv:1312.4615 [math.NT], 2013-2014 (see page 6).
%H A236474 Tim Trudgian, <a href="https://www.emis.de/journals/PIMB/111/16.html">The sum of the unitary divisor function</a>, Publications de l'Institut Mathématique (Beograd), Vol. 97(111), 2015.
%e A236474 The e-divisors of 20 are 10 and 20, sum 30, and its unitary divisors are 1, 4, 5, and 20, also sum 30.
%e A236474 For n=320=2^6*5 we have A051377(n)=(2^6+2^3+2^2+2)*5 = 390 and A034448(n)=(2^6+1)*(5+1) = 390 again.
%Y A236474 Cf. A034448, A051377.
%K A236474 nonn,more
%O A236474 1,2
%A A236474 _Michel Marcus_, Jan 29 2014
%E A236474 More terms from _Andrew Lelechenko_, Feb 06 2014