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A332073
The Silver Comma sequence: Differences of indices of prime terms gives back the sequence; lexicographically earliest such permutation of positive integers.
0
1, 2, 3, 4, 5, 6, 8, 7, 9, 10, 12, 11, 14, 15, 16, 18, 13, 20, 21, 22, 24, 25, 17, 26, 27, 28, 30, 32, 33, 34, 19, 35, 36, 38, 39, 40, 42, 23, 44, 45, 46, 48, 49, 50, 51, 52, 29, 54, 55, 56, 57, 58, 60, 62, 63, 64, 31, 65, 66, 68, 69, 70, 72, 74, 75, 76, 77, 78, 37, 80, 81, 82, 84, 85, 86, 87, 88, 90, 91, 41
OFFSET
1,2
LINKS
Eric Angelini, Yellow commas, pink, red, blue..., personal blog "Cinquante signes" on blogspot.com, May 17 2020
EXAMPLE
The prime terms are at indices 2, 3, 5, 8, 12, 17, 23, 31, 38, 47, 57, 69, 80, 94, ...; first differences give 1, 2, 3, 4, 5, 6, 8, 7, 9, 10, 12, 11, 14, ... = the sequence itself.
PROG
(PARI) upto(N)={local(U=[2]); my(a=Vec([1, 2], N), i=1, L=2, nxt(p)=while(#U>1 && U[2]==U[1]+1, U=U[^1]); my(t=U[1]); until(if(p, t=nextprime(t+1), !isprime(t+=1)) && !setsearch(U, t), ); U=setunion(U, [t]); t); for(n=3, N, a[n]=nxt(n-L==a[i] && i++ && L=n)); a}
CROSSREFS
Cf. A197756 (the Yellow Comma sequence: count digits between odd terms).
Sequence in context: A127388 A307032 A273859 * A117332 A368578 A242704
KEYWORD
nonn
AUTHOR
Eric Angelini and M. F. Hasler, May 19 2020
STATUS
approved