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 A290020 Sort the positive integers according to 3 keys, which are, in order of priority, number of digits, Omega (A001222), and the number itself. 2
 1, 2, 3, 5, 7, 4, 6, 9, 8, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 10, 14, 15, 21, 22, 25, 26, 33, 34, 35, 38, 39, 46, 49, 51, 55, 57, 58, 62, 65, 69, 74, 77, 82, 85, 86, 87, 91, 93, 94, 95, 12, 18, 20, 27, 28, 30, 42, 44 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Ivan Neretin, Table of n, a(n) for n = 1..9999 MATHEMATICA Table[SortBy[Range[10^(n - 1), 10^n - 1], PrimeOmega], {n, 2}] // Flatten (* Michael De Vlieger, Jul 20 2017 *) PROG (PARI) upto(t10nm1) = {my(v, res = []); for(i=1, t10nm1, res = concat(res, vecsort(vector(9*10^(i-1), j, k=j+10^(i-1)-1; [bigomega(k), k])))); vector(#res, i, res[i][2])} (PARI) mycmp(x, y) = my(dd = #digits(x) - #digits(y)); if (dd, sign(dd), sign(bigomega(x) - bigomega(y))); lista(nn) = {v = vector(10^#Str(nn), k, k); w = vecsort(v, mycmp); vector(nn, k, w[k]); } \\ Michel Marcus, Jul 21 2017 CROSSREFS Cf. A001222, A055642, A290019. Sequence in context: A075241 A239694 A097883 * A178595 A098284 A082196 Adjacent sequences:  A290017 A290018 A290019 * A290021 A290022 A290023 KEYWORD nonn,base,easy AUTHOR David A. Corneth, Jul 19 2017 EXTENSIONS Definition clarified by Giovanni Resta, Jul 27 2017 STATUS approved

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Last modified April 18 16:56 EDT 2019. Contains 322229 sequences. (Running on oeis4.)