A337378 Numbers k for which A003961(k) > 2*sigma(k).

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.

Links

Antti Karttunen, Table of n, a(n) for n = 1..20000

Index entries for sequences computed from indices in prime factorization

Index entries for sequences related to sigma(n)

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.

Positions of negative terms in A377984, and in A378751.

Cf. A000203, A003961, A286385.

Cf. A337379 (complement), A337380 (characteristic function).

Sequence in context: A052058 A105732 A339328 * A166319 A271783 A114415

Adjacent sequences: A337375 A337376 A337377 * A337379 A337380 A337381

Keyword

nonn

Author

Antti Karttunen, Aug 27 2020

Status

approved