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A251717
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a(n) = smallest positive integer k such that A083221(k, n) has at most two prime factors (is a prime or semiprime).
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4
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1, 1, 1, 2, 1, 2, 1, 3, 2, 2, 1, 2, 1, 3, 2, 2, 1, 3, 1, 3, 2, 2, 1, 2, 3, 4, 2, 3, 1, 2, 1, 5, 3, 2, 3, 2, 1, 3, 6, 2, 1, 2, 1, 3, 2, 3, 1, 4, 2, 3, 2, 2, 1, 2, 2, 3, 2, 3, 1, 3, 1, 4, 4, 2, 3, 2, 1, 5, 2, 2, 1, 4, 1, 4, 2, 2, 3, 3, 1, 3, 3, 2, 1, 2, 4, 3, 2, 3, 1, 2, 2, 5, 3, 3, 3, 2, 1, 3, 2, 2, 1, 4, 1, 3, 3, 2, 1, 5, 1, 4, 3, 2, 1, 2, 2, 3, 2, 3, 4, 2
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OFFSET
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1,4
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COMMENTS
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Records occur at 1, 4, 8, 26, 32, 39, 238, 462, 1075, 1763, ... with record values 1, 2, 3, 4, 5, 6, 8, 9, 11, 13, ...
New distinct values occur at 1, 4, 8, 26, 32, 39, 238, 306, 462, 1075, 1106, 1763, ... with the values 1, 2, 3, 4, 5, 6, 8, 7, 9, 11, 10, 13, ...
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LINKS
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FORMULA
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PROG
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(Scheme) (define (A251717 n) (let loop ((i 1)) (if (<= (A001222 (A083221bi i n)) 2) i (loop (+ i 1))))) ;; Code for A083221bi given in A083221.
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CROSSREFS
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a(n+1) differs from A057217(n-1) for the first time at n=19, where a(20) = 3, while A057217(18) = 4.
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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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