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Search: id:A112957
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| A112957 |
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a(1) = a(2) = a(3) = 1; for n>1: a(n+3) = a(n)^2 + a(n+1)^2 + a(n+2)^2. |
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3
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| 1, 1, 1, 3, 11, 131, 17291, 298995963, 89398586189293211, 7992107212644486930829797919966571, 63873777698404030240264509605345282496735163325301838600463378485931
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OFFSET
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0,4
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COMMENT
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A quadratic tribonacci sequence.
This is to A000283 as a tribonacci (A000213) is to Fibonacci. Two oddities about his sequence: (a) its first 7 terms are identical to terms numbered 2 through 8 of A072878; (b) only one of the first 9 terms are composite. Primes in the sequence begin 3, 11, 131, 17291 and 89398586189293211. What is the next prime?
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CROSSREFS
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Cf. A000213, A000283, A072878.
Sequence in context: A088075 A088076 A072878 this_sequence A057205 A121897 A067657
Adjacent sequences: A112954 A112955 A112956 this_sequence A112958 A112959 A112960
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KEYWORD
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easy,nonn
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AUTHOR
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Jonathan Vos Post (jvospost3(AT)gmail.com), Jan 02 2006; definition corrected Jan 02 2006
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