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A214364 Irregular triangle read by rows n lists the values k of all decompositions of 2n into unordered sums of two k-almost primes. 0
0, 1, 1, 1, 2, 1, 2, 1, 1, 2, 1, 2, 1, 1, 1, 2, 3, 2, 1, 1, 2, 1, 2, 1, 3, 2, 1, 1, 1, 1, 1, 2, 2, 1, 2, 1, 2, 1, 3, 1, 1, 2, 3, 1, 2, 2, 1, 2, 1, 3, 1, 2, 1, 2, 2, 3, 1, 4, 1, 1, 2, 1, 1, 1, 1, 3, 2, 1, 2, 2, 1, 3, 2, 1, 3, 3, 1, 1, 2, 1, 3, 2, 2, 4, 1, 3, 2, 1, 2, 1, 3, 1, 2, 1, 2, 1, 2, 2, 1, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

COMMENTS

Row n has 1+A214154(n) entries, if n <> 1, where the '1' means the splitting 2*n=n+n into non-distinct k-almost primes is also registered here, but not in A214154. Therefore the last entry in row n is A001222(n) for n > 3.

Row sums are 0, 1, 1, 3, 4, 3, 4, 7, 6, 9, 3, 10, 8, 9, 12, 13, 6, 16, 10, 19, 12, 11, 9, 25, 16, 16, 15, 19, 14, 31, 14, 30, 14, 15, 24,..

LINKS

Table of n, a(n) for n=1..100.

EXAMPLE

If written as a triangle:

0,

1,

1,

1, 2,

1, 2, 1,

1, 2,

1, 2, 1,

1, 1, 2, 3,

2, 1, 1, 2,

1, 2, 1, 3, 2,

1, 1, 1,

1, 1, 2, 2, 1, 3,

1, 2, 1, 3, 1,

1, 2, 3, 1, 2,

2, 1, 2, 1, 3, 1, 2,

1, 2, 2, 3, 1, 4,

1, 1, 2, 1, 1,

1, 1, 3, 2, 1, 2, 2, 1, 3.

CROSSREFS

Cf. A078840. - N. J. A. Sloane, Jul 29 2012

Sequence in context: A300983 A279205 A105690 * A175922 A214856 A006337

Adjacent sequences:  A214361 A214362 A214363 * A214365 A214366 A214367

KEYWORD

nonn,tabf,less

AUTHOR

Juri-Stepan Gerasimov, Jul 23 2012

STATUS

approved

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Last modified September 25 18:13 EDT 2021. Contains 347659 sequences. (Running on oeis4.)