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 A249053 Defined by (i) a(1)=1; (ii) if you move a(n) steps to the right you must reach a prime; (iii) a(n) = smallest unused composite number greater than a(n-1), unless a(n) is required to be prime by (ii), in which case a(n) is the smallest unused prime greater than a(n-1). 2
 1, 2, 4, 5, 6, 8, 11, 12, 13, 14, 17, 18, 20, 23, 24, 25, 26, 29, 30, 31, 32, 37, 38, 41, 42, 44, 45, 47, 48, 53, 54, 55, 59, 60, 62, 63, 67, 68, 71, 72, 73, 74, 79, 80, 81, 82, 83, 84, 89, 90, 97, 98, 101, 102, 104, 105, 106, 108, 109, 110, 113, 114, 115 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 REFERENCES Eric Angelini, Posting to Sequence Fans Mailing List, Mar 17 2008 (the definition was clarified by Gabriel Cunningham). LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 PROG (Haskell) import Data.Map (singleton, findMin, delete, insert) a249053 n = a249053_list !! (n-1) a249053_list = 1 : f 1 1 a002808_list (singleton 1 1) where f x z cs m | k == x = p : f (x + 1) p cs (insert (x + p) 0 \$ delete x m) | otherwise = c : f (x + 1) c cs' (insert (x + c) 0 m) where p = a007918 z (c:cs') = dropWhile (<= z) cs (k, _) = findMin m -- Reinhard Zumkeller, Nov 01 2014 CROSSREFS See A249054 for another version. Cf. A002808, A007918. Sequence in context: A093080 A059916 A099747 * A082851 A091207 A284525 Adjacent sequences: A249050 A249051 A249052 * A249054 A249055 A249056 KEYWORD nonn AUTHOR N. J. A. Sloane, Nov 01 2014 STATUS approved

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Last modified July 15 07:28 EDT 2024. Contains 374324 sequences. (Running on oeis4.)