

A195896


Numbers of the form 2*p1 or 3*p1 where p is 1 or a prime.


1



1, 2, 3, 5, 8, 9, 13, 14, 20, 21, 25, 32, 33, 37, 38, 45, 50, 56, 57, 61, 68, 73, 81, 85, 86, 92, 93, 105, 110, 117, 121, 122, 128, 133, 140, 141, 145, 157, 158, 165, 176, 177, 182, 193, 200, 201, 205, 212, 213, 217, 218, 225, 236, 248, 253, 261, 266, 273, 277, 290, 297, 301, 302, 308
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OFFSET

1,2


LINKS



FORMULA



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;


MATHEMATICA

Union[Flatten[Join[{1, 2}, {2#1, 3#1}&/@Prime[Range[50]]]]] (* Harvey P. Dale, Mar 27 2015 *)


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



