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A341615
Numbers k for which sigma(k) < 2k < A003961(k).
3
4, 8, 9, 10, 14, 15, 16, 21, 27, 32, 35, 39, 44, 45, 49, 50, 52, 57, 63, 64, 68, 69, 75, 76, 81, 91, 92, 98, 99, 105, 110, 116, 117, 124, 125, 128, 130, 135, 136, 147, 148, 152, 153, 154, 164, 165, 170, 171, 172, 175, 182, 184, 188, 189, 190, 195, 207, 212, 225, 230, 231, 232, 236, 238, 242, 243, 244, 245, 248, 250, 255, 256
OFFSET
1,1
COMMENTS
Deficient numbers in A246282.
Not all odd terms are in A337372.
PROG
(PARI)
A003961(n) = { my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };
isA341615(n) = A341613(n);
CROSSREFS
Intersection of A005100 and A246282. Subsequence of A341614.
Cf. A341613 (characteristic function).
Sequence in context: A210998 A205524 A125493 * A164923 A141608 A367768
KEYWORD
nonn
AUTHOR
Antti Karttunen, Feb 22 2021
STATUS
approved