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A358818
a(n) is the least number k such that A046660(k) = A046660(k+1) = n.
1
1, 44, 135, 80, 8991, 29888, 123200, 2316032, 1043199, 24151040, 217713663, 689278976, 11573190656, 76876660736, 311969153024, 2035980763136, 2741258240000, 215189482110975
OFFSET
0,2
COMMENTS
a(14) <= 314944159743.
a(18) > 10^14.5; a(19) = 275892612890624; a(20) > 10^14.5. - Martin Ehrenstein, Dec 11 2022
MATHEMATICA
e[n_] := PrimeOmega[n] - PrimeNu[n]; a[n_] := Module[{k = 1}, While[e[k] != n || e[k + 1] != n, k++]; k]; Array[a, 10, 0]
PROG
(PARI) e(n) = {my(f = factor(n)); bigomega(f) - omega(f)};
a(n) = {my(k=1); while(e(k) != n || e(k+1) !=n , k++); k};
CROSSREFS
Cf. A046660.
Subsequence of A358817.
Similar sequences: A052215, A059737, A093548, A115186.
Sequence in context: A253327 A253320 A230829 * A183642 A183634 A043506
KEYWORD
nonn,more
AUTHOR
Amiram Eldar, Dec 02 2022
EXTENSIONS
a(14)-a(16) from Martin Ehrenstein, Dec 04 2022
a(17) from Martin Ehrenstein, Dec 09 2022
STATUS
approved