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A049051 Numbers k such that k through k+4 all have the same number of divisors. 12

%I #29 Apr 11 2024 04:00:45

%S 11605,12855,13782,19142,21494,28374,28375,40311,42805,50582,55254,

%T 60231,60663,79094,87655,90181,90182,95845,99655,103621,109765,115591,

%U 120727,121045,122151,122871,142454,142806,152630,157493,157494,171893

%N Numbers k such that k through k+4 all have the same number of divisors.

%H Amiram Eldar, <a href="/A049051/b049051.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..1000 from Donovan Johnson)

%t Flatten[Position[Partition[DivisorSigma[0,Range[200000]],5,1],_?(Length[ Union[#]] == 1&),{1},Heads->False]] (* _Harvey P. Dale_, May 30 2014 *)

%t SequencePosition[DivisorSigma[0,Range[200000]],{x_,x_,x_,x_,x_}][[All,1]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Jul 03 2017 *)

%Y Cf. A000005, A006558, A019273, A039665, A119479.

%Y Other runs of equidivisor numbers: A005237 (runs of 2), A005238 (runs of 3), A006601 (runs of 4), A049052 (runs of 6), A049053 (runs of 7).

%K nonn,changed

%O 1,1

%A _David W. Wilson_

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Last modified April 18 11:52 EDT 2024. Contains 371779 sequences. (Running on oeis4.)