A195324 Even numbers that cannot be represented as the sum of an odd prime and a safe prime (A005385).

2, 4, 6, 32, 56, 92, 98, 122, 128, 140, 152, 176, 194, 212, 224, 242, 254, 260, 272, 296, 302, 308, 326, 332, 368, 392, 398, 410, 422, 434, 452, 458, 476, 488, 500, 512, 518, 524, 536, 542, 560, 572, 596, 602, 632, 644, 656, 662, 674, 686, 692, 704, 710, 728

Offset: 1

Author

Dan Brumleve, Sep 15 2011

Keywords

• nonn

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
• StackExchange, Even numbers greater than 6 as sum of two specific primes

Crossrefs

Cf. A000040 (primes), A005385 (safe primes).

Programs

Haskell

a195324 n = a195324_list !! (n-1)
a195324_list = filter p [2,4..] where
   p n = all ((== 0) . a010051) $ takeWhile (> 1) $ map (n -) a005385_list
-- Reinhard Zumkeller, Sep 18 2011

Mathematica

mx = 1000; safe = Select[Prime[Range[PrimePi[mx]]], PrimeQ[(# - 1)/2] &]; p = Prime[Range[2, PrimePi[mx]]]; Complement[Range[2, mx, 2], Union[Flatten[Outer[Plus, p, t]]]] (* T. D. Noe, Sep 15 2011 *)