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Search: id:A136799
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| A136799 |
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Composite runs >2: last term. |
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+0
5
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| 10, 16, 22, 28, 36, 40, 46, 52, 58, 66, 70, 78, 82, 88, 96, 100, 106, 112, 126, 130, 136, 148, 156, 162, 166, 172, 178, 190, 196, 210, 222, 226, 232, 238, 250, 256, 262, 268, 276, 280, 292, 306, 310, 316, 330, 336, 346, 352, 358, 366, 372, 378, 383, 388, 396
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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The program below is useful in testing Grimm's Conjecture, subject of Carlos Rivera's Puzzle 430 in The Prime Puzzles & Problems Connection. Use the program with lines 30 and 70 enabled in the first run, and then disabled with lines 31 and 71 enabled in the second run.
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FORMULA
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Find sequential runs >2 of composite N. All runs will have an odd number of terms.
a(n) = A025584(n+2) -1 . - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jan 24 2008
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EXAMPLE
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a(1)=10 because 10 is the last term in a run of three composites beginning with 8 and ending with 10 (8,9,10).
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PROGRAM
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UBASIC: 10 'puzzle 430 (gap finder) 20 N=1 30 A=1:S=sqrt(N):print N; 31 'A=1:S=N\2:print N; 40 B=N\A 50 if B*A=N and B=prmdiv(B) then print B; 60 A=A+1 70 if A<=sqrt(N) then 40 71 'if A<=N\2 then 40 80 C=C+1:print C 90 N=N+1: if N=prmdiv(N) then C=0:print:stop:goto 90:else 30
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CROSSREFS
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Cf. A136798 A136800 A136801.
Sequence in context: A129848 A083118 A004261 this_sequence A055987 A109100 A104788
Adjacent sequences: A136796 A136797 A136798 this_sequence A136800 A136801 A136802
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KEYWORD
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easy,nonn,uned
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AUTHOR
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Enoch Haga (Enokh(AT)comcast.net), Jan 21 2008
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