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 A075703 a(n) = maximal m such that Sum_{k=n..m} prime(k) <= prime(n)*prime(m). 2
 3, 6, 11, 16, 25, 28, 38, 43, 51, 64, 70, 83, 90, 95, 105, 117, 131, 134, 148, 158, 161, 174, 182, 196, 212, 225, 228, 235, 238, 248, 277, 287, 302, 305, 325, 332, 343, 355, 364, 380, 391, 394, 414, 419, 428, 433, 463, 486, 495, 498, 506, 519, 524, 544, 556 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Robert Israel, Table of n, a(n) for n = 1..3000 Felice Russo, On a problem concerning the Smarandache friendly prime pairs. MAPLE Primes:= [seq(ithprime(i), i=1..1000)]: S:= ListTools:-PartialSums(Primes): f:= proc(n) local m, t;     for m from n do if S[m] > S[n-1] + Primes[n]*Primes[m] then return m-1 fi od end proc: f(1):= 3: map(f, [\$1..100]); # Robert Israel, Aug 08 2019 MATHEMATICA f[n_] := Block[{k = n, s = 0, a = Prime[n]}, While[b = Prime[k]; s = s + b; a*b >= s, k++ ]; k--; k]; Table[ f[n], {n, 1, 55}] CROSSREFS Cf. A074968. Sequence in context: A116940 A278100 A087099 * A267583 A277023 A034029 Adjacent sequences:  A075700 A075701 A075702 * A075704 A075705 A075706 KEYWORD nonn,easy AUTHOR Roger L. Bagula, Oct 02 2002 EXTENSIONS Edited by N. J. A. Sloane and Robert G. Wilson v, Oct 04 2002 Corrected by Robert Israel, Aug 08 2019 STATUS approved

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Last modified May 25 17:19 EDT 2020. Contains 334595 sequences. (Running on oeis4.)