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A082094
A 2nd-order recursion: a(1)=a(2)=1; a(n) = prime(a(n-1)) + primepi(a(n-2)) = A000040(a(n-1)) + A000720(a(n-2)).
3
1, 1, 2, 3, 6, 15, 50, 235, 1498, 12592, 135431, 1806803, 29135476, 555971158, 12336554787, 313733168860, 9034347750986, 291579097035392, 10455240487002922, 413371595329570610
OFFSET
1,3
MATHEMATICA
a[n_]:= a[n]= If[n<4, Fibonacci[n], Prime[a[n-1]] + PrimePi[a[n-2]]]; Table[a[n], {n, 1, 17}] (* modified by G. C. Greubel, Aug 31 2019 *)
PROG
(Magma) a:= func< n | n lt 4 select Fibonacci(n) else NthPrime(Self(n-1)) + #PrimesUpTo(Self(n-2)) >;
[a(n): n in [1..14]]; // G. C. Greubel, Aug 31 2019
CROSSREFS
Sequence in context: A368954 A216144 A121688 * A320963 A061059 A060796
KEYWORD
nonn,more
AUTHOR
Labos Elemer, Apr 11 2003
EXTENSIONS
a(17) from G. C. Greubel, Aug 31 2019
a(18)-a(20) from Chai Wah Wu, Sep 18 2019
STATUS
approved