A179892 Numbers which are not the sum of three distinct members of twin primes.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, 17, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120

Offset

1,2

Comments

All positive even numbers are terms of the sequence:

members of twin primes are odd and the sum of three odd primes is odd.

No odd numbers >=19 are in the sequence (conjecture?).

Links

Table of n, a(n) for n=1..68.

Example

15=3+5+7, 19=3+5+11 hence 15 and 19 are not in the sequence.

Mathematica

pr=Prime[Range[100]]; se=Select[pr, PrimeQ[ #-2]||PrimeQ[ #+2]&];
se2=Select[Union[Total/@Subsets[se, {3}]], #<200&]; Complement[Range[200], se2]

Crossrefs

Cf. A007534 Even numbers which are not the sum of a pair of twin primes.

Sequence in context: A343822 A303550 A164563 * A348519 A061773 A125007

Adjacent sequences: A179889 A179890 A179891 * A179893 A179894 A179895

Keyword

nonn

Author

Zak Seidov, Jul 30 2010

Status

approved