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 A322025 Ordinal transform of A322023. 2
 1, 1, 2, 2, 3, 1, 4, 1, 3, 1, 5, 1, 6, 2, 1, 2, 7, 1, 8, 1, 1, 4, 9, 1, 10, 2, 5, 2, 11, 1, 12, 1, 1, 3, 2, 1, 13, 3, 3, 1, 14, 1, 15, 1, 2, 6, 16, 1, 7, 1, 3, 3, 17, 2, 2, 1, 2, 8, 18, 1, 19, 9, 1, 4, 1, 1, 20, 3, 4, 2, 21, 1, 22, 2, 2, 2, 3, 1, 23, 1, 24, 3, 25, 1, 1, 4, 5, 3, 26, 1, 1, 5, 3, 10, 5, 1, 27, 3, 2, 1, 28, 1, 29, 1, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Positions where 1, 2, 3, 4, 5, ... occur for the first time are 1, 3, 5, 7, 11, 13, 17, 19, 23, 25, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 81, 83, 89, 97, 101, 103, 107, 109, 113, 121, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 187, 191, 193, ... Note that this is not a subsequence of A000961; for example, 187 = 11*17 is a semiprime. LINKS Antti Karttunen, Table of n, a(n) for n = 1..65537 PROG (PARI) \\ Needs also code from A322023. ordinal_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), pt); for(i=1, length(invec), if(mapisdefined(om, invec[i]), pt = mapget(om, invec[i]), pt = 0); outvec[i] = (1+pt); mapput(om, invec[i], (1+pt))); outvec; }; v322025 = ordinal_transform(v322023); A322025(n) = v322025[n]; CROSSREFS Cf. A000010, A002322, A081373, A303753, A303755, A303756, A303777, A322023. Sequence in context: A318545 A071450 A175457 * A339526 A072078 A322316 Adjacent sequences:  A322022 A322023 A322024 * A322026 A322027 A322028 KEYWORD nonn AUTHOR Antti Karttunen, Dec 01 2018 STATUS approved

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Last modified May 21 08:31 EDT 2022. Contains 353898 sequences. (Running on oeis4.)