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.

A349868 Nobly abundant numbers (A349758) that are not abundant numbers (A005101).

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%I A349868 #11 Dec 06 2021 03:11:55
%S A349868 315,495,525,585,675,693,735,765,819,825,850,855,884,950,975,988,1012,
%T A349868 1035,1071,1078,1125,1150,1196,1197,1210,1215,1274,1275,1276,1287,
%U A349868 1292,1305,1323,1364,1395,1425,1449,1450,1508,1550,1564,1612,1617,1628,1665,1666
%N A349868 Nobly abundant numbers (A349758) that are not abundant numbers (A005101).
%C A349868 This sequence if infinite. For example, 45*p is a term if p is a prime > 5.
%H A349868 Amiram Eldar, <a href="/A349868/b349868.txt">Table of n, a(n) for n = 1..10000</a>
%e A349868 315 is a term since it is not abundant, A000203(315) = 624 < 2*315 = 630, and both A000005(315) = 12 and A000203(315) = 624 are abundant numbers.
%t A349868 abQ[n_] := DivisorSigma[1, n] > 2*n; nobAbQ[n_] := And @@ abQ /@ DivisorSigma[{0, 1}, n]; Select[Range[2000], !abQ[#] && nobAbQ[#] &]
%Y A349868 Intersection of A263837 and A349758.
%Y A349868 Cf. A000005, A000203, A005101, A349869.
%K A349868 nonn
%O A349868 1,1
%A A349868 _Amiram Eldar_, Dec 03 2021