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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 Robert Israel, Table of n, a(n) for n = 1..15 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 Adjacent sequences: A339942 A339943 A339944 * A339946 A339947 A339948 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.)