|
|
|
|
1, 2, 3, 2, 5, 6, 7, 3, 10, 11, 12, 13, 14, 15, 17, 12, 19, 20, 21, 22, 23, 5, 26, 28, 29, 30, 31, 33, 34, 35, 6, 37, 38, 39, 41, 42, 43, 44, 45, 46, 47, 7, 20, 51, 52, 53, 55, 57, 58, 59, 60, 61, 62, 63, 65, 66, 67, 68, 69, 70, 71, 73, 74, 45, 76, 77, 78, 79
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
With the exception of the first term, each term appears exactly two times.
|
|
LINKS
|
|
|
MATHEMATICA
|
Min /@ Transpose@ {#, Table[k = 1; While[! IntegerQ[(k #)^(1/3)], k++] &@ #[[n]]; k, {n, Length@ #}]} &@ Select[Range@ 80, FreeQ[FactorInteger@ #, {_, k_ /; k > 2}] &] (* Michael De Vlieger, Nov 10 2016, after Jan Mangaldan at A004709 *)
|
|
PROG
|
\\ List of the first about n terms (probably a bit more).
(PARI) lista(n) = {n = ceil(1.21*n); my(l=List([1]), f); forprime(p=2, n, for(i=1, #l, if(l[i]*p<=n, listput(l, l[i] *p); if(l[i] * p^2<=n, listput(l, l[i]*p^2))))); listsort(l); for(i=2, #l, f=factor(l[i]); f[, 2] = vector(#f[, 2], i, 3-(f[i, 2]%3))~; l[i] = min(l[i], factorback(f))); l} \\ David A. Corneth, Nov 01 2016
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|