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A104576
Indices of primes in A001644 (the Lucas 3-step numbers).
6
2, 3, 4, 7, 8, 9, 10, 12, 20, 30, 33, 66, 76, 77, 82, 87, 98, 180, 205, 360, 553, 719, 766, 1390, 1879, 1999, 4033, 5620, 16506, 17436, 23676, 24428, 27758, 31932, 58199, 67661, 85040, 102023, 185595
OFFSET
1,1
COMMENTS
The sequence of generalized tribonacci numbers is defined as beginning with 1, 3, 7. Subsequent terms are the sum of the previous three terms. Note that the sequence of these generalized tribonacci numbers has many more primes than the tribonacci sequence A000073 (whose prime indices are in A092835).
a(40) > 2*10^5. - Robert Price, Dec 24 2013
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
FORMULA
A001644(a(n)) = A105762(n). - Arthur O'Dwyer, Jul 26 2024
CROSSREFS
Cf. A104577 (indices of prime generalized tetranacci numbers).
Sequence in context: A231003 A171551 A096199 * A332485 A031477 A047227
KEYWORD
nonn,more
AUTHOR
T. D. Noe, Mar 16 2005
EXTENSIONS
a(37)-a(39) from Robert Price, Dec 24 2013
Name clarified by Arthur O'Dwyer, Jul 25 2024
STATUS
approved