A180636 Positive integers that are divisible by neither 8k-1 nor 8k+1, for all k > 0.

1, 2, 3, 4, 5, 6, 8, 10, 11, 12, 13, 16, 19, 20, 22, 24, 26, 29, 32, 37, 38, 40, 43, 44, 48, 52, 53, 58, 59, 61, 64, 67, 74, 76, 80, 83, 86, 88, 96, 101, 104, 106, 107, 109, 116, 118, 122, 128, 131, 134, 139, 148, 149, 152, 157, 160, 163, 166, 172, 173, 176, 179, 181, 192

Offset: 1

Author

Glenn G. Chappell, Sep 13 2010

Keywords

• easy
• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 1..5000

Crossrefs

Cf. A047424. - Robert G. Wilson v, Oct 06 2010

Programs

Mathematica

fQ[n_] := Union[ MemberQ[{1, 7}, # ] & /@ Union@ Mod[ Rest@ Divisors@ n, 8]] == {False}; fQ[1] = True; Select[ Range@ 200, fQ] (* Robert G. Wilson v, Oct 06 2010 *)

Python

# Works in Python 2 or 3
import itertools
for n in itertools.count(1):
    for k in range(1, 2+n//8):
        if n%(8*k-1)==0 or n%(8*k+1)==0:
            break
    else:
        print(n)

Extensions

More terms from Robert G. Wilson v, Oct 06 2010