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A209493
Indices of primes in sequence A006190.
3
2, 5, 11, 17, 61, 103, 167, 193, 293, 643, 647, 911, 11243, 29437, 55021
OFFSET
1,1
COMMENTS
Index must be prime. The indices greater than 293 yield probable primes.
MATHEMATICA
seq=RecurrenceTable[{a[n]==3*a[n-1]+a[n-2], a[1]==1, a[2]==3}, a, {n, 1000}]; Select[Range[1000], PrimeQ[seq[[#]]]&]
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Vaclav Kotesovec, Mar 09 2012
EXTENSIONS
a(14)-a(15) from Vaclav Kotesovec, Sep 08 2013
STATUS
approved