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A107768 Integers p*q*r such that p*q and q*r are both golden semiprimes (A108540). Integers p*q*r such that p = A108541(j), q = A108542(j) = A108541(k) and r = A108542(k). 1
30, 1309, 50209, 299423, 4329769, 4661471, 13968601, 19867823, 49402237, 90419171, 95575609, 230236057 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Golden 3-almost primes.

Volumes of bricks (rectangular parallelopipeds) each of whose faces has golden semiprime area. How long a chain is possible of the form p(1) * p(2) * p(3) * ... * p(n) where each successive pair of values are factors of a golden semiprime? That is, if Zumkeller's golden semiprimes are the 2-dimensional case and the present sequence is the 3-dimensional case, is there a maximum n for an n-dimensional case?

LINKS

Table of n, a(n) for n=1..12.

EXAMPLE

30 = 2 * 3 * 5, where both 2*3=6 and 3*5=15 are golden semiprimes.

1309 = 7 * 11 * 17.

50209 = 23 * 37 * 59.

CROSSREFS

Cf. A014612, A108540, A108541, A108542.

Sequence in context: A163521 A273416 A002456 * A048536 A000173 A055351

Adjacent sequences:  A107765 A107766 A107767 * A107769 A107770 A107771

KEYWORD

easy,nonn

AUTHOR

Jonathan Vos Post, Jun 11 2005

STATUS

approved

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Last modified April 27 06:52 EDT 2017. Contains 285508 sequences.