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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
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
Sequence in context: A075241 A239694 A097883 * A178595 A098284 A082196
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 March 29 10:22 EDT 2024. Contains 371268 sequences. (Running on oeis4.)