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A339945 Numbers y such that sqrt(6*y^2+10)-3 is prime. 2
3, 13, 31, 129, 29180479, 121378881, 110778874246369293, 263631110418336671, 95129083120198558843838970225921, 213007829848951141529011991896053267187 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
sqrt(p + (p^2-1)/6) for p in A339935.
Primes in this sequence include 3, 13, 31. Are there any others?
LINKS
EXAMPLE
a(3) = 31 is a term because sqrt(6*31^2+10)-3 = 73 is prime.
MAPLE
g:= gfun:-rectoproc({a(i+4)-10*a(i+2)+a(i)=0, a(0)=1, a(1)=3, a(2)=13, a(3)= 31}, a(i), remember):
select(y -> isprime(sqrt(6*y^2+10)-3), map(g, [$1..100]));
CROSSREFS
Cf. A339935.
Sequence in context: A213970 A034050 A107689 * A154834 A159047 A219971
KEYWORD
nonn
AUTHOR
J. M. Bergot and Robert Israel, Dec 23 2020
STATUS
approved

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Last modified May 18 19:36 EDT 2024. Contains 372666 sequences. (Running on oeis4.)