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 A160218 Index at which n-th prime occurs in A160256, or -1 if the prime never occurs. 2
 2, 3, 14, 20, 32, 301, 1065 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS A160256(a(n))=A000040(n) if and only if both Conjectures 1 and 2 are true: Conjecture 1: Primes occur in A160256 in increasing order. Conjecture 2: All primes occur in A160256. Conjecture 3: Except for A160256(4)=4, the least positive integer which does not occur in A160256 up to a given index is always a prime (and thus of the form A160256(a(k)) for some k). Conjecture 4: A160256(a(n)) is always the least positive integer which did not occur earlier in A160256. LINKS PROG (PARI) list_A160218(n)={ my(a1=1, a2=1, S=[]); until( isprime(a1) & !print1(#S, ", ") & !n--, for( a=1, 9e9, a*a1%a2 & next; setsearch(S, a) & next; a2=a1; S=setunion(S, Set(a1=a)); /*print1(a", "); */ next(2)); error); vecsort(eval(S)) } CROSSREFS Cf. A160256, A151413. Sequence in context: A266694 A284928 A294405 * A208983 A337609 A081615 Adjacent sequences:  A160215 A160216 A160217 * A160219 A160220 A160221 KEYWORD hard,more,nonn AUTHOR M. F. Hasler, May 06 2009 EXTENSIONS Edited by N. J. A. Sloane, May 16 2009 STATUS approved

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Last modified August 18 10:34 EDT 2022. Contains 356212 sequences. (Running on oeis4.)