A174550 Run lengths of 2 or larger for consecutive prime numbers in A006577.
3, 2, 2, 2, 2, 2, 4, 2, 3, 3, 2, 2, 3, 3, 4, 2, 5, 4, 3, 2, 3, 4, 2, 2, 2, 2, 3, 3, 2, 5, 2, 2, 3, 2, 3, 2, 2, 3, 8, 2, 4, 2, 2, 2, 2, 2, 3, 3, 3, 6, 3, 4, 2, 2, 3, 3, 2, 2, 4, 2, 2, 3, 6, 2, 3, 2, 2, 2, 5, 2, 2, 2, 2, 2, 2, 2, 5, 3, 2, 4, 3, 5, 3, 3, 2, 8, 2, 2, 2, 2, 3, 8, 4, 3, 3, 3, 4, 2, 3, 8, 2, 3, 3, 5, 3
Offset: 1
Examples
a(1) = 3 represents the run (7, 2, 5). a(2) = 2 represents the run (3, 19). a(3) = 2 represents the run (17, 17). a(7) = 4 represents the run (19, 19, 107, 107). a(12956) = 55 represents the run (83, 251, 83, 251, 127, 127, 127, 251, 83, 83, 83, 83, 83, 83, 83, 83, 83, 251, 83, 83, 83, 83, 83, 83, 101, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 251, 251, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83, 83)
Programs
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Maple
nn:=2000:T:=array(1..nn):for n from 1 to nn do: m:=n:for p from 0 to 1000 while (m<>1) do: if irem(m,2)=1 then m:=3*m+1:else m:=m/2:fi:od:T[n]:=p:od:ii:=1:for i from 1 to nn do:if type(T[i],prime)=true and type(T[i+1],prime)=true then ii:=ii+1:else if ii<>1 then printf(`%d, `, ii):ii:=1:else fi:fi:od:
Comments