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.

A353034 Numbers m such that tau(m) = 2 * tau(m + 1) and simultaneously sigma(m) = 2 * sigma(m + 1), where tau(k) = A000005(k) and sigma(k) = A000203(k).

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%I A353034 #8 May 07 2022 10:40:02
%S A353034 20118,20712,79338,103410,203898,267630,570342,907710,1093026,1228062,
%T A353034 1263918,1663752,2322760,3268782,3468486,3527250,5483418,6277038,
%U A353034 6500442,7637980,9181578,9297078,17708178,18638646,25274946,25364526,25768302,25909254,31118664
%N A353034 Numbers m such that tau(m) = 2 * tau(m + 1) and simultaneously sigma(m) = 2 * sigma(m + 1), where tau(k) = A000005(k) and sigma(k) = A000203(k).
%C A353034 Corresponding values of tau(m): 16, 16, 16, 32, 16, 32, 16, 32, 16, 32, 16, 32, 32, ...
%C A353034 Corresponding values of sigma(m): 46080, 51840, 181440, 276480, 432000, 701568, 1200960, 2211840, ...
%e A353034 tau(20118) = 16 = 2 * tau(20119) = 2 * 8, sigma(20118) = 46080 = 2 * sigma(20119) = 2 * 23040.
%o A353034 (Magma) [m: m in [2..10^6] | #Divisors(m) eq 2 * #Divisors(m + 1) and &+Divisors(m) eq 2 * &+Divisors(m + 1)]
%Y A353034 Cf. A000005 (tau), A000203 (sigma), A054004, A347603, A353033.
%Y A353034 Subsequence of A163193.
%K A353034 nonn
%O A353034 1,1
%A A353034 _Jaroslav Krizek_, Apr 18 2022