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 A228916 Indices of primes in sequence A108300. 1
 1, 3, 9, 15, 39, 225, 231, 363, 687, 1299, 1335, 1809, 2367, 12735 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Conjecture: for n>1 a(n) is a multiple of 3. Next term > 92000. The indices greater than 363 yield probable primes. - Vaclav Kotesovec, Oct 28 2013 LINKS MATHEMATICA seq=RecurrenceTable[{a[n]==3*a[n-1]+a[n-2], a[0]==1, a[1]==5}, a, {n, 1, 1000}]; Select[Range[1000], PrimeQ[seq[[#]]]&] CROSSREFS Cf. A108300, A209493, A001605, A001606, A096650, A099088. Sequence in context: A013581 A133997 A057909 * A082702 A214771 A065917 Adjacent sequences:  A228913 A228914 A228915 * A228917 A228918 A228919 KEYWORD nonn,hard,more AUTHOR Vaclav Kotesovec, Sep 08 2013 STATUS approved

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Last modified April 16 23:40 EDT 2021. Contains 343051 sequences. (Running on oeis4.)