A342609 Positive integers that cannot be written in the form k - gpf(k) +- 1 for some integer k, where gpf(k) is the greatest prime factor of k.
17, 49, 161, 197, 199, 209, 251, 391, 419, 449, 649, 685, 769, 799, 883, 967, 1057, 1189, 1249, 1301, 1457, 1481, 1681, 1793, 1937, 1979, 2001, 2029, 2089, 2177, 2209, 2311, 2377, 2379, 2419, 2431, 2449, 2549, 2551, 2575, 2591, 2705, 2729, 2899, 3041, 3073
Offset: 1
Keywords
Links
- Robert Israel, Table of n, a(n) for n = 1..10000
Programs
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Maple
f:= proc(n) local g; g:= max(numtheory:-factorset(n)); n-g+1,n-g-1 end proc: sort(convert({$1..5000} minus map(f, {$1..10001}),list)); # Robert Israel, Apr 12 2021