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A171095 Triangle read by rows: row n contains sequence S_n = [s(1), ..., s(n)] where s(1) is the least semiprime pq such that the recurrence s(i+1) = sum of two prime factors of s(i) generates a chain of exactly n semiprimes. 0
4, 9, 6, 14, 9, 6, 33, 14, 9, 6, 62, 33, 14, 9, 6, 177, 62, 33, 14, 9, 6, 886, 445, 94, 49, 14, 9, 6, 2649, 886, 445, 94, 49, 14, 9, 6, 5294, 2649, 886, 445, 94, 49, 14, 9, 6, 68653, 5294, 2649, 886, 445, 94, 49, 14, 9, 6, 496966, 248485, 49702, 24853, 886 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..60.

EXAMPLE

Triangle begins:

4

9, 6

14, 9, 6

33, 14, 9, 6

62, 33, 14, 9, 6

177, 62, 33, 14, 9, 6

886, 445, 94, 49, 14, 9, 6

2649, 886, 445, 94, 49, 14, 9, 6

5294, 2649, 886, 445, 94, 49, 14, 9, 6

68653, 5294, 2649, 886, 445, 94, 49, 14, 9, 6

496966, 248485, 49702, 24853, 886, 445, 94, 49, 14, 9, 6

1490889, 496966, 248485, 49702, 24853, 886, 445, 94, 49, 14, 9, 6

16896262, 8448133, 496966, 248485, 49702, 24853, 886, 445, 94, 49, 14, 9, 6

185858761, 16896262, 8448133, 496966, 248485, 49702, 24853, 886, 445, 94, 49, 14, 9, 6

...

CROSSREFS

Sequence in context: A053667 A218072 A261023 * A075065 A141553 A095065

Adjacent sequences:  A171092 A171093 A171094 * A171096 A171097 A171098

KEYWORD

nonn,tabl

AUTHOR

N. J. A. Sloane, Sep 23 2010, based on a posting to the Sequence Fans Mailing List by Hans Havermann, Sep 10 2010

STATUS

approved

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Last modified April 19 18:37 EDT 2019. Contains 322290 sequences. (Running on oeis4.)