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.

A225758 Runs of consecutive numbers with the same number and sum of divisors.

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%I A225758 #17 Jan 19 2019 04:15:43
%S A225758 14,15,1334,1335,1634,1635,2685,2686,33998,33999,42818,42819,64665,
%T A225758 64666,84134,84135,109214,109215,122073,122074,166934,166935,289454,
%U A225758 289455,383594,383595,440013,440014,544334,544335,605985,605986,649154,649155,655005,655006
%N A225758 Runs of consecutive numbers with the same number and sum of divisors.
%C A225758 No triple found up to 10^9.
%H A225758 Donovan Johnson, <a href="/A225758/b225758.txt">Table of n, a(n) for n = 1..1000</a>
%e A225758 Sequence begins:
%e A225758 14, 15;
%e A225758 1334, 1335;
%e A225758 1634, 1635;
%e A225758 2685, 2686;
%e A225758 33998, 33999;
%e A225758 etc.
%t A225758 sel = Select[Range[1000000], DivisorSigma[0, #] == DivisorSigma[0, #+1] && DivisorSigma[1, #] == DivisorSigma[1, #+1] &]; Union[sel, sel+1]
%Y A225758 Cf. A225756 (same number of divisors), A225757 (same sum of divisors).
%Y A225758 Cf. A054004 (first term of every run).
%K A225758 nonn,easy
%O A225758 1,1
%A A225758 _Jean-François Alcover_, May 15 2013