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 A099722 From a 2-dimensional walk involving primes. 0
 11, 17, 23, 41, 47, 67, 83, 103, 157, 257, 277, 3407, 3517, 3547 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Start with 7 in the center cell. Rules: Write prime(n-1) in a cell and, if Prime(n-1) == 1 mod 5, then move to upper cell, append prime(n) to the cell. if Prime(n-1) == 2 mod 5, then move to right cell, append prime(n) to the cell. if Prime(n-1) == 3 mod 5, then move to lower cell, append prime(n) to the cell. if Prime(n-1) == 4 mod 5, then move to left cell, append prime(n) to the cell. Sequence gives sequence of primes appearing in the cell to the right of center cell. There are no more terms below 10^10. But two-dimensional random walks are recurrent, so this sequence is heuristically infinite. [Charles R Greathouse IV, Oct 18 2011] LINKS EXAMPLE .................. 13 ...... 13 ......... 13 .............. 13 ................. 7 -> 7 : 11 -> 7 : 11 -> 7 : 11,17 -> 7 : 11,17 : 19 -> 7 : 11,17,23 : 19 -> ... PROG (PARI) upto(lim)=my(x=-1, y=0, p=7); forprime(q=11, lim, if(p%5>2, if(p%5==3, y--, x--), if(p%5==1, y++, x++)); if(!x&&!y, print1(q", ")); p=q) \\ Charles R Greathouse IV, Oct 18 2011 CROSSREFS Cf. A096447. Sequence in context: A063638 A141250 A096454 * A031505 A094524 A098412 Adjacent sequences:  A099719 A099720 A099721 * A099723 A099724 A099725 KEYWORD nonn,more,changed AUTHOR Yasutoshi Kohmoto (zbi74583(AT)boat.zero.ad.jp), Nov 06 2004 EXTENSIONS a(8)-a(14) from Sean A. Irvine, Oct 18 2011 STATUS approved

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