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.
%I A124275 #11 Oct 21 2018 06:24:29
%S A124275 2,5,181
%N A124275 Terms of A123856 that are not terms of A124273.
%C A124275 Primes that divide A123855(p-1) = Sum_{j=1..p-1} Sum_{i=1..p-1} prime(i)^j but not A124271(p) = Sum_{i=1..p} (prime(i)^p - 1)/(prime(i) - 1).
%C A124275 The next term if it exists is greater than 1000.
%C A124275 The next term A124275(4), if it exists, is larger than 25000. (Checked by calculating sequences A123856 and A124273 to 1200 terms.) - _M. F. Hasler_, Nov 10 2006
%e A124275 A123856(n) begins {2, 3, 5, 7, 13, 17, 19, 31, 47, 59, 61, 71, 101, 103, 107, 109, 137, 149, 151, 157, 167, 181, 197, ...}.
%e A124275 A124273(n) begins {3, 7, 13, 17, 19, 31, 47, 59, 61, 71, 101, 103, 107, 109, 137, 149, 151, 157, 167, 197, ...}.
%e A124275 Thus a(1) = 2, a(2) = 5, a(3) = 181.
%p A124275 A124275:=proc(n) option remember; local i1,i2; i1:=1:i2:=1: # find index i1 such that A123856[i1] is > A124275[n-1]; # then continue until A124273 "jumped over" the term A123856[i1] # while n>1 and A123856(i1) <= procname(n-1) or A123856(i1) = A124273(i2) do i1:=i1+1: # find index i2 such that A124273[i2] is >= A123856(i1) # while A124273(i2) < A123856(i1) do i2:=i2+1: od: od: A123856(i1) end; # _M. F. Hasler_, Nov 10 2006
%Y A124275 Cf. A123855, A123856, A124271, A124273.
%K A124275 bref,hard,more,nonn
%O A124275 1,1
%A A124275 _Alexander Adamchuk_, Oct 23 2006