A067784 - OEIS

%I #17 Feb 11 2021 01:40:41

%S 1,2,3,4,5,6,8,10,12,15,16,20,24,29,30,40,45,48,56,60,64,65,80,92,105,

%T 111,120,144,146,160,180,182,212,232,240,246,336,340,344,348,360,376,

%U 439,470,476,580,624,680,709,819,832,914,984,1020,1058,1290,1341,1352

%N Numbers k such that prime(k+1)^4 == prime(k)^4 (mod k).

%H Robert Israel, <a href="/A067784/b067784.txt">Table of n, a(n) for n = 1..300</a>

%p q:= 2: count:= 0:

%p for n from 1 while count < 100 do

%p   p:= q; q:= nextprime(p);

%p   if q^4 - p^4 mod n = 0 then count:= count+1; A[count]:= n; fi;

%p od:

%p seq(A[i],i=1..count); # _Robert Israel_, May 16 2017

%t Select[Range[100], Mod[Prime[# + 1]^4 , #] == Mod[Prime[#]^4, #] &] (* _G. C. Greubel_, May 17 2017 *)

%Y Cf. A030514, A067785.

%K nonn

%O 1,2

%A _Benoit Cloitre_, Feb 06 2002