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 A328578 Index of the least prime not dividing A276086(A276086(n)): a(n) = A257993(A276087(n)). 24
 2, 1, 3, 1, 4, 1, 3, 1, 4, 1, 5, 1, 2, 1, 5, 1, 4, 1, 3, 1, 6, 1, 6, 1, 2, 1, 6, 1, 7, 1, 2, 1, 4, 1, 3, 1, 3, 1, 5, 1, 6, 1, 2, 1, 6, 1, 6, 1, 3, 1, 7, 1, 7, 1, 2, 1, 7, 1, 5, 1, 2, 1, 5, 1, 4, 1, 3, 1, 6, 1, 6, 1, 2, 1, 7, 1, 7, 1, 3, 1, 7, 1, 8, 1, 2, 1, 6, 1, 8, 1, 2, 1, 6, 1, 7, 1, 3, 1, 7, 1, 7, 1, 2, 1, 7, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS Index of the least significant zero digit in the primorial base expansion of A276086(n), when the rightmost digit is in the position 1. The scatter plot shows both regular looking as well as more chaotic regions. This can be more clearly seen in related A328579. See also A328839. LINKS Antti Karttunen, Table of n, a(n) for n = 0..32768 Rémy Sigrist, Density plot of the sequence for n = 0..510510 FORMULA a(n) = A328570(A276086(n)) = A257993(A276087(n)) = A055396(A328403(n)). a(n) = A000720(A328579(n)). a(n) = A257993(n) + A328590(n). a(n) = A055396(A328763(n)). For all n >= 0, a(A328761(n)) = n. PROG (PARI) A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); }; A328570(n) = { my(i=1, p=2); while(n && (n%p), i++; n = n\p; p = nextprime(1+p)); (i); }; A328578(n) = A328570(A276086(n)); (PARI) A257993(n) = { for(i=1, oo, if(n%prime(i), return(i))); } A328578(n) = A257993(A276086(A276086(n))); CROSSREFS Cf. A000720, A055396, A276086, A276087, A328403, A328570, A328579 (the corresponding prime), A328590, A328763, A328766, A328839. Cf. A328585 (where equal with A257993), A328587 (less than), A328588 (greater than). Cf. A328761 (the first occurrence of each n). Cf. also array A328631 and its rows A005408, A328632, A328633, A328634, A328635, A328636 (positions of terms 1 .. 6 in this sequence). Sequence in context: A332422 A229944 A218533 * A094741 A285577 A324392 Adjacent sequences:  A328575 A328576 A328577 * A328579 A328580 A328581 KEYWORD nonn,look AUTHOR Antti Karttunen, Oct 20 2019 STATUS approved

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Last modified January 21 10:22 EST 2022. Contains 350476 sequences. (Running on oeis4.)