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 A175839 Smallest runs of n*2-1 consecutive composites. 0
 4, 8, 9, 10, 24, 25, 26, 27, 28, 90, 91, 92, 93, 94, 95, 96, 114, 115, 116, 117, 118, 119, 120, 121, 122, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Even lengths of runs of composites are omitted, as nontrivial runs always have odd lengths (see A046933). Run 5 (starting at 114) has 13 consecutive composites and is repeated in runs 6 and 7. Run 8 starts at 524 = A008950(6). LINKS Wikipedia, Composite number EXAMPLE Run 1 has length 1; the first composite is 4. Run 2 has length 3; the first three consecutive composites are 8, 9, and 10. Run 3 has length 5; the first five consecutive composites are 24, 25, 26, 27, and 28. 4; 8, 9, 10; 24, 25, 26, 27, 28; 90, 91, 92, 93, 94, 95, 96; 114, 115, 116, 117, 118, 119, 120, 121, 122; 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124; 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126; PROG (Python) from sympy import isprime out = [] run = 1 for n in range(4, 10000):     isrun = True     for o in range(run): isrun *= not isprime(n + o - run)     if isrun:         for o in range(run): out.append(n + o - run)         run += 2 print(out) CROSSREFS Cf. A002808, A046933, A008950. Sequence in context: A073042 A094349 A118715 * A226085 A104623 A228653 Adjacent sequences:  A175836 A175837 A175838 * A175840 A175841 A175842 KEYWORD easy,nonn AUTHOR Grant Garcia, Sep 20 2010 STATUS approved

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Last modified May 27 21:14 EDT 2022. Contains 354110 sequences. (Running on oeis4.)