OFFSET
1,2
EXAMPLE
a(1)=1 because p=1 and 2*1 - 1 = 1;
a(2)=2 because p=1 and 3*1 - 1 = 2;
a(3)=3 because p=2 and 2*2 - 1 = 3;
a(4)=5 because p=2 and 3*3 - 1 = 5 or p=3 and p=2 and 3*2 - 1 = 5;
a(5)=8 because p=3 and 3*3 - 1 = 8.
MAPLE
isA195896 := proc(n)
for p in {(n+1)/2, (n+1)/3} do
if type(p, 'integer') then
if isprime(p) or p = 1 then
return true;
end if;
end if;
end do;
false ;
end proc:
for n from 1 to 400 do
if isA195896(n) then
printf("%d, ", n) ;
end if;
end do: # R. J. Mathar, Oct 15 2011
MATHEMATICA
Union[Flatten[Join[{1, 2}, {2#-1, 3#-1}&/@Prime[Range[50]]]]] (* Harvey P. Dale, Mar 27 2015 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Juri-Stepan Gerasimov, Sep 24 2011
STATUS
approved