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A273048 a(1)=5; thereafter a(n) is the least prime p such that a(n-1)+p is the average of some twin prime pair. 0
5, 7, 11, 19, 23, 37, 71, 79, 101, 127, 293, 307, 311, 331, 479, 541, 761, 859, 863, 1009, 1019, 1063, 1277, 1381, 1409, 1759, 1823, 1999, 2003, 2017, 2111, 2131, 2141, 2281, 2357, 3061, 3137, 3163, 3389, 3391, 3557, 3571, 3761, 4327, 4493, 4507, 4733, 4987, 5021, 5119, 5153, 5179, 5279, 5431, 5507, 5563, 5927, 6043, 6197, 6343 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
EXAMPLE
For n=1, a(1)=5; then a(2)=7 because a(2)+a(1) = 5+7 = 12 = (11+13)/2 and (11,13) are twin primes.
a(3)=11 because a(3)+a(2) = 11+7 = 18 = (17+19)/2 and (17,19) are twin primes.
PROG
(PARI) {
a=5; b=a; sm=1; print1(a", ");
while(sm<60,
b=nextprime(b+1);
if(isprime(a+b-1)&&isprime(a+b+1),
a=b; sm+=1; print1(b", ")
)
)
}
CROSSREFS
Cf. A014574.
Sequence in context: A116641 A288446 A213981 * A240621 A040127 A341215
KEYWORD
nonn
AUTHOR
Dimitris Valianatos, May 13 2016
STATUS
approved

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Last modified May 20 08:05 EDT 2024. Contains 372703 sequences. (Running on oeis4.)