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A097620 Numbers having more prime factors than their neighbors together. 2
12, 16, 18, 24, 30, 32, 36, 40, 42, 48, 54, 60, 64, 72, 84, 88, 90, 96, 102, 108, 112, 120, 128, 132, 138, 140, 144, 150, 156, 160, 162, 168, 180, 192, 198, 200, 210, 216, 224, 228, 234, 240, 250, 252, 256, 264, 270, 272, 280, 282, 288, 294, 300, 304, 306, 308 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Michael S. Branicky, Table of n, a(n) for n = 1..10000

FORMULA

{k: A001222(k) > A001222(k-1) + A001222(k+1)}. - Michael S. Branicky, Dec 16 2021

EXAMPLE

A001222(64) = A001222(2^6) = 6, A001222(64-1) = A001222(3*3*7) = 3, A001222(64+1) = A001222(5*13) = 2, and 6 > 3+2, therefore 64 is a term.

PROG

(Python)

from sympy import primeomega

def ok(n): return primeomega(n) > primeomega(n-1) + primeomega(n+1)

print([k for k in range(2, 309) if ok(k)]) # Michael S. Branicky, Dec 16 2021

CROSSREFS

Subsequence of A097619.

Cf. A001222.

Sequence in context: A107308 A051518 A043544 * A335222 A356863 A112548

Adjacent sequences: A097617 A097618 A097619 * A097621 A097622 A097623

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Aug 17 2004

STATUS

approved

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Last modified December 3 01:25 EST 2022. Contains 358510 sequences. (Running on oeis4.)