A244930 Indices of primes in A214831.
3, 4, 7, 8, 16, 26, 34, 42, 78, 94, 101, 107, 216, 255, 543, 562, 851, 981, 1099, 1528, 1824, 1955, 2122, 2488, 2500, 15331, 15961, 24107, 24938, 26051, 58504, 61617, 81034, 85119, 89768, 90597, 97191, 116899, 195346
Offset: 1
Keywords
Links
- 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
Crossrefs
Programs
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Mathematica
a={1,9,9}; For[n=3, n<=1000, n++, sum=Plus@@a; If[PrimeQ[sum], Print[n]]; a=RotateLeft[a]; a[[3]]=sum] Flatten[Position[LinearRecurrence[{1,1,1},{1,9,9},200000],?PrimeQ]]-1 (* The prime number at index 195346 (term a(39) of this sequence) has 51699 digits, so this program takes a long time to run. *) (* _Harvey P. Dale, Dec 29 2019 *)
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