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
J.-M. Falcoz, Table of n, a(n) for n = 1..70
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
KEYWORD
nonn
AUTHOR
Eric Angelini, Jan 07 2012
EXTENSIONS
First 70 terms computed by Jean-Marc Falcoz, Jan 09 2012
STATUS
approved