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A060048
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a(1) = 1 and for n>1 a(n) = Max { q prime | q# < prime(n)# / q# } where prime(i) = A000040(i) and p(i)# = A002110(i), primorial.
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1
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1, 2, 2, 3, 5, 5, 7, 11, 11, 13, 13, 17, 19, 19, 23, 23, 29, 31, 31, 37, 37, 41, 43, 43, 47, 47, 53, 53, 59, 61, 61, 67, 67, 71, 71, 73, 79, 79, 83, 83, 89, 97, 97, 101, 101, 103, 103, 107, 109, 109, 113, 113, 127, 127, 131, 131, 137, 139, 139, 149, 149, 151, 151, 157
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OFFSET
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1,2
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LINKS
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EXAMPLE
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prime(10) = 29: 2*3*5*7*11*13 < 17*19*23*29 and as 2*3*5*7*11*13*17 > 19*23*29 we have a(10) = 13.
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PROG
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(PARI) primo(n) = factorback(primes(n)); \\ A002110
a(n) = {if (n==1, 1, my(iq=2, P= primo(n)); while (sqr(primo(iq))<P, iq++); prime(iq-1); ); } \\ Michel Marcus, Mar 04 2022
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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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