A064408 Even numbers not the sum of a pair of the greater of the twin primes.

2, 4, 6, 8, 16, 22, 28, 30, 34, 40, 42, 46, 52, 54, 58, 60, 64, 70, 72, 76, 82, 84, 88, 90, 94, 96, 98, 100, 102, 106, 112, 118, 120, 124, 126, 130, 132, 136, 138, 142, 148, 150, 154, 160, 162, 166, 168, 172, 174, 178, 180, 184, 190, 192, 196

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Example

The greater of the twin primes < 200 are 5, 7, 13, 19, 31, 43, 61, 73, 103, 109, 139, 151, 181, 193, 199. 22 is in the above sequence because no combination of any two numbers from the set just enumerated can be summed to make 22.

Maple

N:= 300: # to get all terms <= N
T:= select(t -> isprime(t) and isprime(t-2), {5, seq(6*i+1, i=1..N/6)}):
A:= {seq(i, i=2..N, 2)} minus {seq(seq(T[i]+T[j], j=1..i), i=1..nops(T))}:
sort(convert(A, list)); # Robert Israel, Mar 14 2018

Mathematica

q = Select[ Range[ 200 ], PrimeQ[ # - 2 ] && PrimeQ[ #2 ] & ]; Complement[ Table[ n, {n, 2, 200, 2} ], Union[ Flatten[ Table[ q[ [ i ] ] + q[ [ j ] ], {i, 1, Length[ q ] }, {j, 1, i} ] ] ] ]
upto=200; Module[{gtp=Transpose[Select[Partition[Prime[Range[PrimePi[ upto]]], 2, 1], #[[2]]-#[[1]]==2&]][[2]]}, Complement[Range[2, upto, 2], Total/@ Tuples[gtp, 2]]] (* Harvey P. Dale, Jan 17 2015 *)

Crossrefs

Sequence in context: A353867 A356956 A379169 * A316225 A100685 A296993

Adjacent sequences: A064405 A064406 A064407 * A064409 A064410 A064411

Keyword

nonn

Author

Robert G. Wilson v, Sep 29 2001

Status

approved