login
Numbers that cannot be written as the sum of a prime number and a primorial number.
0

%I #6 Aug 02 2015 13:25:03

%S 1,2,10,16,22,26,27,28,34,36,40,46,50,51,52,56,57,58,64,66,70,76,78,

%T 82,86,87,88,92,93,94,96,100,106,112,116,117,118,120,121,122,123,124,

%U 125,126,130,134,135,136,142,144,146,147,148,149,154,156,160,162,166,170

%N Numbers that cannot be written as the sum of a prime number and a primorial number.

%F {k : A175933(k)=0}. - _R. J. Mathar_, Nov 03 2010

%t fQ[n_] := Block[{pp = Select[ FoldList[Times, 1, Prime@ Range@ 20], # <= n &]}, Last@ Union@ PrimeQ[n - pp] == False]; Select[ Range@ 170, fQ] (* _Robert G. Wilson v_, Nov 05 2010 *)

%Y Cf. A118954, A175933.

%K nonn

%O 1,2

%A _Juri-Stepan Gerasimov_, Oct 29 2010

%E Corrected (90 removed) and extended by _R. J. Mathar_ and _Robert G. Wilson v_, Nov 03 2010