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A280996
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Prime Matula-Goebel numbers of generalized Bethe trees.
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5
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2, 3, 5, 7, 11, 17, 19, 23, 31, 53, 59, 67, 83, 97, 103, 127, 131, 227, 241, 277, 311, 331, 419, 431, 509, 563, 661, 691, 709, 719, 739, 1433, 1523, 1543, 1619, 1787, 1879, 2063, 2221, 2309, 2437, 2897, 3001, 3637, 3671, 3803, 4091, 4637, 4943, 5189, 5381
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OFFSET
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1,1
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COMMENTS
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Also prime numbers p whose index pi(p) is the Matula-Goebel number of a planted achiral tree.
An alternative definition: prime(n) is in the sequence iff n is a perfect power of a prime number already in the sequence.
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LINKS
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FORMULA
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a(1) = 2; a(n+1) = prime(A214577(n)).
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EXAMPLE
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a(n) = prime(Product_{i in y} a(i)) where y is the n-th partition in the following sequence, which spans all constant partitions: 1,2,11,3,4,111,22,5,1111,6,7,8,33,222,9,11111,44,...
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MATHEMATICA
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nn=10000;
BTQ[n_]:=Or[n===1, MatchQ[PrimePi/@FactorInteger[n][[All, 1]], {_?BTQ}]];
Prime/@Select[Range[PrimePi[nn]], BTQ]
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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