cp's OEIS Frontend

A378028 Positions of records in A377059.

%I A378028 #9 Nov 17 2024 07:29:56
%S A378028 1,4,9,17,22,25,46,49,81,118,121,169,243,334,337,343,361,529,841,961,
%T A378028 1331,1369,2187,2197,2209,2809,3481,3721,4489,5041,6241,6859,6889,
%U A378028 7921,10201,11449,12167,14641,16129,17161,19321,22201,24389,26569,27889,29791,29929,32041,32761,38809,39601,44521,49729
%N A378028 Positions of records in A377059.
%C A378028 Numbers k such that A377059(k) > A377059(j) for all j < k.
%C A378028 The record values are in A378029.
%C A378028 It appears that in most cases a(n) is in A244623 (Odd prime powers that are not primes) and A378029(n) = A000010(a(n)).
%C A378028 If p is in A001122 and is not a Wieferich prime (A001220), then p^2 is a term with A377059(p^2) = p*(p-1).
%F A378028 A378029(n) = A377059(a(n)).
%e A378028 a(3) = 9 is a term because A377059(9) = 6 > A377059(k) for all k < 9.
%p A378028 f:= proc(n) local x,r;
%p A378028   for x from 2 to n do
%p A378028     if igcd(x,n) <> 1 then next fi;
%p A378028     r:= numtheory:-order(x,n);
%p A378028     if r::even and r < n-1 then return r fi
%p A378028   od;
%p A378028   0
%p A378028 end proc:
%p A378028 J:= 1: m:= 0: count:= 0:
%p A378028 for k from 2 while count < 100 do
%p A378028 v:= f(k);
%p A378028 if v > m then m:= v; J:= J,k; count:= count+1 fi;
%p A378028 od:
%p A378028 J;
%Y A378028 Cf. A000010, A001122, A001220, A244623, A377059, A378029.
%K A378028 nonn
%O A378028 1,2
%A A378028 _Robert Israel_, Nov 14 2024