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 A024697 a(n) = p(1)p(n) + p(2)p(n-1) + ... + p(k)p(n+1-k), where k = [ (n+1)/2 ], p = A000040 = the primes. 18
 4, 6, 19, 29, 68, 94, 177, 231, 400, 484, 753, 903, 1340, 1552, 2157, 2489, 3352, 3784, 5013, 5515, 7052, 7758, 9773, 10575, 13076, 14076, 17023, 18339, 21876, 23414, 27715, 29437, 34570, 36500, 42335, 44731, 51560, 54198, 61955, 65051, 73700, 77402, 87293 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(n) = A025129(n) for even n. - M. F. Hasler, Apr 06 2014 LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 MAPLE A024697:=n->sum( ithprime(k)*ithprime(n-k+1), k=1..(n+1)/2 ); seq(A024697(n), n=1..50); # Wesley Ivan Hurt, Apr 06 2014 MATHEMATICA Table[Sum[Prime[k] Prime[n - k + 1], {k, (n + 1)/2}], {n, 50}] (* Wesley Ivan Hurt, Apr 06 2014 *) PROG (PARI) A024697(n)=sum(k=1, (n+1)\2, prime(k)*prime(n-k+1)) \\ M. F. Hasler, Apr 06 2014 (Haskell) a024697 n = a024697_list !! (n-1) a024697_list = f (tail a000040_list) [head a000040_list] 2 where f (p:ps) qs k = sum (take (div k 2) \$ zipWith (*) qs \$ reverse qs) : f ps (p : qs) (k + 1) -- Reinhard Zumkeller, Apr 07 2014 CROSSREFS Cf. A014342, A000040. Sequence in context: A013160 A153777 A034189 * A024874 A095383 A116383 Adjacent sequences: A024694 A024695 A024696 * A024698 A024699 A024700 KEYWORD nonn AUTHOR Clark Kimberling EXTENSIONS Name edited and values double-checked by M. F. Hasler, Apr 06 2014 STATUS approved

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Last modified September 27 19:23 EDT 2023. Contains 365714 sequences. (Running on oeis4.)