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A337382
Numbers k for which A003973(k) < 2*sigma(k).
4
1, 2, 3, 4, 5, 7, 10, 11, 13, 17, 19, 22, 23, 25, 26, 29, 31, 33, 34, 37, 38, 39, 41, 43, 46, 47, 51, 53, 55, 57, 58, 59, 61, 62, 65, 67, 69, 71, 73, 74, 77, 79, 82, 83, 85, 86, 87, 89, 91, 93, 94, 95, 97, 101, 103, 106, 107, 109, 111, 113, 115, 116, 118, 119, 121, 122, 123, 127, 129, 131, 133, 134, 137, 139, 141
OFFSET
1,2
PROG
(PARI)
A003973(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); sigma(factorback(f)); };
isA337382(n) = (A003973(n)<2*sigma(n));
CROSSREFS
Cf. A337381 (complement).
Positions of zeros in A337383.
Subsequence of A337379.
Cf. also A246281.
Sequence in context: A191925 A160512 A144430 * A348253 A157082 A133493
KEYWORD
nonn
AUTHOR
Antti Karttunen, Aug 27 2020
STATUS
approved