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.

A344655 Numbers k such that A032741(k-1)+A065608(k+1) is divisible by k.

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%I A344655 #10 May 26 2021 12:48:15
%S A344655 1,2,5,7,32767
%N A344655 Numbers k such that A032741(k-1)+A065608(k+1) is divisible by k.
%C A344655 Numbers k such that Sum_{j|k-1} (k mod j) + Sum_{j|k+1} (k mod j) is divisible by k.
%C A344655 a(6) > 10^8 if it exists.
%e A344655 a(5) = 32767 is a term because A032741(32767-1)+A065608(32768+1) = 15+65519 = 65534 = 2*32767.
%p A344655 filter:= proc(p) local d;
%p A344655 (numtheory:-tau(p-1) + numtheory:-sigma(p+1) - numtheory:-tau(p+1)-1) mod p = 0
%p A344655 end proc:
%p A344655 select(filter, [$1..10^5]);
%Y A344655 Cf. A032741, A065608.
%K A344655 nonn,more
%O A344655 1,2
%A A344655 _J. M. Bergot_ and _Robert Israel_, May 25 2021