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.

A105440 Highly cototient numbers that are prime, or intersection of A000040 and A100827.

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%I A105440 #36 Dec 22 2024 12:15:55
%S A105440 2,23,47,59,83,89,113,167,269,389,419,509,659,839,1049,1259,1889,2099,
%T A105440 2309,2729,3359,3989,4289,4409,5879,6089,6719,9029,9239,10289,10709,
%U A105440 11549,13649,13859,15329,15959,20789,21839,23099,25409,27299,30029,34649,43889,51869
%N A105440 Highly cototient numbers that are prime, or intersection of A000040 and A100827.
%C A105440 2 is definitely a "highly cototient prime". Oddly enough, though, PrimeFan does not list it as safe prime that is also a highly cototient number in RNTFS00013 even though he considers 1 to be a prime. - Robert Happelberg (roberthappelberg(AT)yahoo.com), Oct 04 2005
%C A105440 115 of the first 229 terms (just over 50%) of A100827 are prime. - _Jud McCranie_, May 18 2017
%H A105440 Amiram Eldar, <a href="/A105440/b105440.txt">Table of n, a(n) for n = 1..115</a>
%H A105440 PrimeFan, <a href="http://primefan.tripod.com/EsotericIntegerSequences.html">Listing of Esoteric Integer Sequences</a>, See RNTFS00013, RNTFS00014.
%H A105440 PrimeFan, <a href="/A031214/a031214.pdf">Esoteric Integer Sequences</a> [Cached copy]
%e A105440 269 (after 59 & 89) is the first prime in a sequence of primes which are congruent to 9 mod 10.
%Y A105440 Cf. A000040, A100827.
%K A105440 nonn
%O A105440 1,1
%A A105440 _Paul Muljadi_, Sep 22 2005
%E A105440 More terms from Robert Happelberg (roberthappelberg(AT)yahoo.com), Oct 04 2005
%E A105440 More terms from _T. D. Noe_, Mar 16 2010
%E A105440 More terms from _Amiram Eldar_, Dec 24 2020