login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A343974 Even numbers k such that the two sets of primes in the Goldbach representation of k and k+2 as the sum of two odd primes do not intersect. 0

%I #23 Jun 24 2021 02:46:39

%S 38,68,80,98,122,128,146,158,164,188,206,212,218,224,248,278,290,302,

%T 308,326,332,338,344,368,374,380,398,410,416,428,440,458,476,488,500,

%U 518,530,536,542,548,554,578,584,608,614,626,632,638,668,674,692,698,710

%N Even numbers k such that the two sets of primes in the Goldbach representation of k and k+2 as the sum of two odd primes do not intersect.

%C k is in the sequence iff the Goldbach representation of k as the sum of two odd primes does not contain any prime that is the lesser of a twin prime (A001359).

%C Conjecture: a(n) is congruent to 2 mod 6 with a(n)-3 not prime.

%H Mahdi Meisami and Carlos Rivera, <a href="https://www.primepuzzles.net/puzzles/puzz_1040.htm">Puzzle 1040. Pair of consecutive even integers such that ...</a>, The Prime Puzzles & Problems Connection.

%F a(n) = 6*A046953(n) + 2 (conjectured). - _Hugo Pfoertner_, Jun 09 2021

%e The Goldbach representations of 80 and 82 as the sum of two odd primes are:

%e {{73, 7}, {67, 13}, {61, 19}, {43, 37}} and {{79, 3}, {71, 11}, {59, 23}, {53, 29}, {41, 41}}. The two sets {7, 13, 19, 37, 43, 61, 67, 73} and {3, 11, 23, 29, 41, 53, 59, 71, 79} do not intersect, so 80 is a term of the sequence.

%t Select[Range[6,1000,2],!IntersectingQ@@(Flatten@Select[IntegerPartitions[#,2],And@@PrimeQ[#]&]&/@{#,#+2})&]

%Y Cf. A001359, A046953.

%K nonn

%O 1,1

%A _Giorgos Kalogeropoulos_, Jun 07 2021

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 24 10:55 EDT 2024. Contains 375410 sequences. (Running on oeis4.)