OFFSET
1,1
LINKS
James C. McMahon, Table of n, a(n) for n = 1..10000
EXAMPLE
18 is in this sequence because:
(a) 18 is average of twin prime pair {17, 19};
(b) the largest odd divisor of 18 is 9;
(c) 9 is the midpoint of the cousin prime pair {7, 11}.
MATHEMATICA
lod[m_]:=Select[Divisors[m+1], OddQ][[-1]]; Select[Prime[Range[1130]], PrimeQ[#+2]&&PrimeQ[lod[#]-2]&&PrimeQ[lod[#]+2]&]+1 (* James C. McMahon, Nov 17 2024 *)
PROG
(Magma) [n: n in [4..10^4] | IsPrime(n-1) and IsPrime(n+1) and IsPrime((n div 2^Valuation(n, 2))-2) and IsPrime((n div 2^Valuation(n, 2))+2)];
CROSSREFS
KEYWORD
nonn
AUTHOR
Juri-Stepan Gerasimov, Oct 19 2024
STATUS
approved