A371656 - OEIS

A371656

Numbers k such that k - 2 and k + 2 have the same number of prime factors, counted with multiplicity.

5, 8, 9, 10, 12, 15, 21, 23, 24, 36, 37, 38, 39, 45, 53, 58, 60, 67, 68, 69, 81, 84, 86, 89, 93, 99, 100, 102, 105, 110, 111, 112, 113, 117, 120, 121, 129, 131, 134, 138, 143, 144, 154, 157, 165, 172, 173, 178, 184, 185, 188, 195, 203, 204, 207, 211, 215, 216, 217, 219, 225, 230, 231, 240, 244

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OFFSET

1,1

COMMENTS

Numbers k such that A001222(k - 2) = A001222(k + 2).

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

EXAMPLE

a(4) = 10 is a term because 10 - 2 = 8 = 2^3 and 10 + 2 = 12 = 2^2 * 3 are both products of 3 primes, counted with multiplicity.

MAPLE

M:= map(numtheory:-bigomega, [$1..10^3]):

select(k -> M[k-2] = M[k+2], [$3 .. 10^3 - 2]);