OFFSET
2,1
COMMENTS
a(n) <= A213529(n).
LINKS
Robert Israel, Table of n, a(n) for n = 2..3000
EXAMPLE
a(3) = 905 because it is the smallest de Polignac number (A006285) divisible by the third prime.
MAPLE
N:= 10^5: # to use de Polignac numbers <= N
P:= select(isprime, {2, seq(i, i=3..N, 2)}):
dP:= {seq(i, i=1..N, 2)}:
for k from 0 to ilog2(N) do
dP:= dP minus map(`+`, P, 2^k)
od:
for m from 2 do
R:= ListTools:-SelectFirst(1, t -> t mod P[m] = 0, dP);
if R = {} then break fi;
A[m]:= R[1];
od:
seq(A[i], i=2..m-1); # Robert Israel, Sep 06 2016
PROG
(Magma) lst:=[]; for r in [2..45] do p:=NthPrime(r); n:=-p; f:=0; while IsZero(f) do n:=n+2*p; k:=-1; repeat k+:=1; a:=n-2^k; until a lt 1 or IsPrime(a); if a lt 1 then Append(~lst, n); f:=1; end if; end while; end for; lst;
CROSSREFS
KEYWORD
nonn
AUTHOR
Arkadiusz Wesolowski, Sep 03 2016
STATUS
approved