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A337378
Numbers k for which A003961(k) > 2*sigma(k).
5
16, 24, 27, 32, 36, 40, 45, 48, 49, 54, 56, 63, 64, 72, 80, 81, 84, 90, 96, 98, 99, 100, 104, 105, 108, 112, 117, 120, 125, 126, 128, 135, 140, 144, 147, 152, 153, 160, 162, 168, 171, 175, 176, 180, 184, 189, 192, 196, 198, 200, 207, 208, 210, 216, 224, 225, 234, 240, 243, 245, 248, 250, 252, 256, 264, 270, 272, 273
OFFSET
1,1
COMMENTS
Note that A003961(n) >= sigma(n) for all n. See A286385.
PROG
(PARI)
A003961(n) = { my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };
isA337378(n) = (A003961(n)>2*sigma(n));
CROSSREFS
Subsequence of A246282 and of A337381.
Cf. A337379 (complement), A337380 (characteristic function).
Sequence in context: A052058 A105732 A339328 * A166319 A271783 A114415
KEYWORD
nonn
AUTHOR
Antti Karttunen, Aug 27 2020
STATUS
approved