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A227885
Primes in the union of all n-step Lucas sequences.
2
2, 3, 7, 11, 29, 31, 47, 71, 113, 127, 131, 191, 199, 223, 239, 241, 367, 439, 443, 521, 863, 983, 1013, 1499, 1871, 2003, 2207, 3571, 6553, 8087, 8191, 9349, 16369, 32647, 32707, 36319, 63487, 65407, 65519, 122401, 126719, 131071, 196331, 260111, 524287
OFFSET
1,1
LINKS
T. D. Noe, Table of n, a(n) for n = 1..1000 (first 383 terms from Robert Price)
Tony D. Noe and Jonathan Vos Post, Primes in Fibonacci n-step and Lucas n-step Sequences, J. of Integer Sequences, Vol. 8 (2005), Article 05.4.4
FORMULA
2 and the primes in A127208.
MATHEMATICA
plst={2}; plimit=10^39; For[n=2, n<=3+Log[2, plimit], n++, llst={}; For[i=1, i<n, i++, AppendTo[llst, -1]]; AppendTo[llst, n]; For[k=2, k<=2*(1+Log[GoldenRatio, plimit*Sqrt[5]+0.5]), k++, sum=Sum[llst[[j+k-2]], {j, 1, n}]; AppendTo[llst, sum]; If[sum<=plimit && PrimeQ[sum], AppendTo[plst, sum]]]]; Union[plst]
KEYWORD
nonn
AUTHOR
Robert Price, Oct 25 2013
STATUS
approved