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.

A337933 Numbers that are the sum of two abundant numbers in exactly one way.

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%I A337933 #10 Feb 14 2021 13:16:41
%S A337933 24,30,32,38,40,44,50,52,56,58,62,64,70,957,963,965,969,975,981,985,
%T A337933 987,993,999,1001,1005,1011,1015,1017,1023,1025,1029,1033,1035,1041,
%U A337933 1045,1047,1049,1053,1057,1059,1065,1071,1077,1083,1085,1089,1095,1101,1105,1107,1113
%N A337933 Numbers that are the sum of two abundant numbers in exactly one way.
%C A337933 An easy to calculate upper bound for terms is 12*(A047802(2)+1) = 64696932312. This and all larger numbers can be expressed as the sum of an abundant multiple of 6 and a multiple of A047802(2) in at least two ways. - _Peter Munn_, Feb 09 2021
%e A337933 24 is in the sequence since it is the sum of two abundant numbers in exactly one way as 24 = 12 + 12.
%e A337933 30 is in the sequence since it is the sum of two abundant numbers in exactly one way as 30 = 12 + 18.
%t A337933 Table[If[Sum[(1 - Sign[Floor[(2 (n - i))/DivisorSigma[1, n - i]]])*(1 - Sign[Floor[(2 i)/DivisorSigma[1, i]]]), {i, Floor[n/2]}] == 1, n, {}], {n, 1200}] // Flatten
%Y A337933 Cf. A005101, A047802, A048242.
%K A337933 nonn,fini
%O A337933 1,1
%A A337933 _Wesley Ivan Hurt_, Oct 01 2020