login
A369182
Numbers k such that d(k) is greater than d(k-2), d(k-1), d(k+1) and d(k+2) where d(k) is the number of divisors of k.
0
12, 24, 30, 36, 48, 60, 66, 72, 80, 84, 90, 96, 100, 108, 112, 120, 126, 132, 140, 144, 150, 156, 160, 165, 168, 176, 180, 192, 204, 210, 216, 220, 224, 228, 234, 240, 252, 256, 260, 264, 270, 276, 280, 288, 294, 300, 312, 315, 320, 324, 330, 336, 357, 360, 364, 368, 372
OFFSET
1,1
EXAMPLE
30 is a term since d(28) = 6, d(29) = 2, d(30) = 8, d(31) = 2, d(32) = 6 and 6 < 8 > 6, 2 < 8 > 2.
MATHEMATICA
SequencePosition[Table[DivisorSigma[0, n], {n, 1, 400}], {a_, b_, c_, d_, e_} /; Max[a, b, d, e] < c][[;; , 1]] + 2 (* Amiram Eldar, Jan 16 2024 *)
CROSSREFS
Cf. A000005.
Subsequence of A075027.
Sequence in context: A334799 A352287 A364462 * A108938 A085236 A068567
KEYWORD
nonn
AUTHOR
Zhicheng Wei, Jan 15 2024
STATUS
approved