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A221218
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Let sequence B_n={b_m} be defined by: b_1=prime(n), b_2=prime(n+1); for m>=3, b_m=b_(m-2)+b_(m-1) if b_(m-2)+b_(m-1) is not semiprime, otherwise b_m is the least prime divisor of b_(m-2)+b_(m-1). Then a(n) is the maximal term of sequence B_n, or a(n)=0 if B_n is unbounded.
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0
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570, 570, 570, 570, 19726, 113750, 570, 22534, 570, 570, 570, 570, 399610, 570, 570, 570, 3138, 670, 570, 570, 772, 570, 570, 2448, 109472, 570, 570, 570, 1150, 609, 18644, 71049, 2276, 570, 1634, 1552, 13844, 798, 68830, 6940, 575, 1498, 668, 2551, 1586, 29729, 1748, 113750, 19726, 1435, 194650, 64360, 3213, 953988, 9146, 16539, 811, 8370238, 516878, 881, 99942, 7399, 4160, 215843, 8397, 676, 13397, 1715, 915722, 702, 3572, 141759, 1192, 1131, 762, 24895, 1194, 22534, 1750, 7069, 68830
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OFFSET
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1,1
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COMMENTS
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Conjecture: All a(n)>=570. Conjecture: All sequences B_n are eventually periodic.
Moreover, our first observations show that up to n=8, the lengths of the periods is 36.
Peter J. C. Moses extended these observations and confirmed the same length 36 of all periods up to n=209.
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LINKS
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EXAMPLE
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In case n=1, B_1 essentially coincides with A214156 and thus a(1)=570 which is the maximal term of A214156.
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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