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A203985 Lexicographically earliest permutation of the primes such that successive absolute differences yield a permutation of all nonprime numbers. 2
2, 3, 13, 47, 197, 11, 29, 443, 397, 1321, 4831, 15559, 211, 5, 19, 41, 293, 113, 971, 419, 2687, 1087, 1709, 5851, 23629, 83, 17341, 65171, 268969, 20753, 690607, 4273, 1289, 81931, 56267, 3025961, 6343, 41927, 1455241, 14255011, 21557, 733, 44351, 7 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
It is only conjectured that this sequence is a permutation of the primes and that the successive differences yield all composite integers. The definition is rather to be understood as "The next term is chosen as the smallest prime not occurring earlier such that the successive absolute differences only yield 1 or composite numbers, and none of these occurs twice." - M. F. Hasler, Jan 09 2012
LINKS
E. Angelini, An array of naturals, Jan 07 2012
E. Angelini, An array of naturals [Cached copy, with permission]
PROG
(PARI) {extend_first_row(a=[], u=[])=u||for(i=1, #a, u=setunion(u, Set(a[i])); forstep(j=i-1, 1, -1, u=setunion(u, Set(a[j]=abs(a[j]-a[j+1]))))); for(t=1, 9e9, isprime(t)||next; setsearch(u, t)&&next; my(tt=t, new=Set(t)); forstep(j=#a, 1, -1, setsearch(u, tt=abs(tt-a[j]))&&next(2); isprime(tt)&&next(2); setsearch(new, tt)&&next(2); new=setunion(new, Set(tt))); return(t))} \\ M. F. Hasler, Jan 09 2012
CROSSREFS
Sequence in context: A206776 A275556 A214888 * A164511 A184256 A105050
KEYWORD
nonn
AUTHOR
Eric Angelini, Jan 07 2012
EXTENSIONS
First 70 terms computed by Jean-Marc Falcoz, Jan 09 2012
STATUS
approved

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Last modified March 19 07:04 EDT 2024. Contains 370953 sequences. (Running on oeis4.)