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A073819 a(n) = prime(i) such that prime(i)*(n+1-i) is maximized (1 <= i <= n). 2
2, 2, 2, 5, 5, 11, 11, 11, 11, 17, 17, 17, 17, 29, 29, 29, 29, 29, 37, 37, 37, 41, 41, 41, 41, 59, 59, 59, 59, 59, 59, 59, 67, 67, 67, 71, 71, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 97, 127, 127, 127, 127, 127, 127, 127, 127, 149, 149, 149, 149, 149, 149, 149, 149 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

3 is the only n for which the maximum is not unique; a(3) could also be given as 3.

LINKS

Table of n, a(n) for n=1..65.

FORMULA

a(n) = A073818(n)/A073820(n).

EXAMPLE

For n = 5, we take the first 5 primes in ascending order and multiply them by the numbers from 5 to 1 in descending order: 2*5 = 10 3*4 = 12 5*3 = 15 7*2 = 14 11*1 = 11 The largest product is 15, so a(5) = 5.

CROSSREFS

Cf. A073818, A073820.

Sequence in context: A326547 A326686 A096403 * A190846 A214787 A066835

Adjacent sequences:  A073816 A073817 A073818 * A073820 A073821 A073822

KEYWORD

easy,nonn

AUTHOR

David Wasserman, Aug 13 2002

STATUS

approved

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Last modified April 22 14:33 EDT 2021. Contains 343177 sequences. (Running on oeis4.)