A128303 - OEIS

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A128303

Indices of squares (of semiprimes) in the 4-almost primes.

1, 3, 8, 12, 24, 29, 59, 66, 90, 97, 162, 172, 187, 224, 234, 335, 385, 412, 489, 531, 551, 630, 692, 791, 921, 997, 1128, 1223, 1256, 1285, 1420, 1484, 1518, 1549, 1937, 2146, 2315, 2441, 2483, 2556, 2606, 2651, 2915, 3124, 3175, 3542, 3587, 3645, 3751, 3800

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OFFSET

1,2

COMMENTS

A014613(a(n)) = A074985(n) = A001358(n)^2.

LINKS

Table of n, a(n) for n=1..50.

EXAMPLE

a(5) = 24 as 196=14^2=semiprime(5)^2, the 5th square in the 4-almost primes, is the 24th 4-almost prime.

CROSSREFS

Cf. A128302, A014613, A074985, A001358, A128304.

Sequence in context: A209934 A007434 A379717 * A123906 A065970 A326890