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 A290489 Upper ends of record gaps between numbers that are either prime or twice a prime. 5
 3, 10, 53, 191, 478, 538, 1082, 1277, 1346, 2498, 3299, 5147, 12889, 20849, 28277, 31454, 338098, 520526, 546461, 1050706, 1761289, 1965077, 3467038, 6085103, 27348949, 27915898, 111108917, 113652593, 230126531, 231902434, 327764249, 438981203, 581755523, 1837981759, 2489382911 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The gap between 31397 and 31454 is due to the record prime gap between 31397 and 31469 being almost exactly twice the record prime gap between 15683 and 15727. LINKS Giovanni Resta, Table of n, a(n) for n = 1..40 FORMULA a(n) = A290488(n) + A290541(n). EXAMPLE a(3) = 53 because the next number that is a prime or twice a prime after 47 is 53, and that is a record gap of size 6. MATHEMATICA p = op = 2; r = 0; Reap[While[p < 10^6, p++; If[PrimeQ[p] || PrimeQ[p/2], g = p - op; If[g > r, Sow@p; r = g]; op = p]]][[2, 1]] (* Giovanni Resta, Aug 04 2017 *) CROSSREFS Cf. A001751, A290488, A290541. Sequence in context: A013201 A309885 A052446 * A002873 A309910 A042171 Adjacent sequences:  A290486 A290487 A290488 * A290490 A290491 A290492 KEYWORD nonn AUTHOR Bobby Jacobs, Aug 03 2017 EXTENSIONS a(17)-a(35) from Giovanni Resta, Aug 04 2017 STATUS approved

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Last modified May 13 14:47 EDT 2021. Contains 343860 sequences. (Running on oeis4.)