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.

A158846 Primes which are removed with the algorithm of A156284, starting the selection with the interval (2^4, 2^5).

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%I A158846 #8 May 12 2019 02:17:32
%S A158846 19,29,41,47,53,59,61,97,149,167,173,233,239,251,271,283,313,331,349,
%T A158846 373,409,433,439,499,509,521,557,563,593,641,677,743,761,797,827,887,
%U A158846 911,941,953,1013,1019,1021,1039,1051,1129,1171,1237,1279,1291
%N A158846 Primes which are removed with the algorithm of A156284, starting the selection with the interval (2^4, 2^5).
%C A158846 We iteratively scan integer intervals (2^(m-1)..2^m), first the one with m=5, then m=6, m=7, etc., and start with the set S={3,5,7,11,...} of all odd primes. For each prime p = 2^m-k, 2^(m-1) < p < 2^m, p is removed from S if k is in S. Basically, all the upper primes of primes pairs are removed when the prime pair sums to a power of 2 which are larger than 2^4. The sequence shows all p that are removed from S at any stage m.
%C A158846 Powers 2^m, m >= 5, are not expressible as sums of two primes which are not in the sequence.
%p A158846 A158846 := proc()
%p A158846         local mmax,prrem,m,prm,pi,p,q ;
%p A158846         mmax := 12 ; prrem := {} ;
%p A158846         for m from 5 to mmax do
%p A158846                 prm := {} ;
%p A158846                 for pi from 1 do
%p A158846                         k := ithprime(pi) ;
%p A158846                         p := 2^m-k ;
%p A158846                         if p <= 2^(m-1) then  break; end if;
%p A158846                         if isprime(p) and not k in prrem then prm := prm union {p} ;
%p A158846                         end if ;
%p A158846                 end do:
%p A158846                 prrem := prrem union prm ;
%p A158846         end do: print( sort(prrem)) ; return ;
%p A158846 end proc:
%p A158846 A158846() ; # _R. J. Mathar_, Dec 07 2010
%Y A158846 Cf. A156284, A158756, A156759.
%K A158846 nonn
%O A158846 1,1
%A A158846 _Vladimir Shevelev_, Mar 28 2009