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A120397 Minimal number of steps needed to represent a prime >=5 as a sum of at most 3 primes such that all the previous odd primes are represented. 0
1, 2, 2, 3, 3, 4, 4, 4, 5, 5, 6, 6, 7, 7, 7, 8, 8, 9, 10, 10, 11, 11, 11, 12, 13 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

This sequence contains probably every natural number, though this should be checked further. Conjecture: Every prime >=5 can be represented as a sum of at most 3 primes, such that all the previous odd primes are represented.

LINKS

Table of n, a(n) for n=1..25.

EXAMPLE

5=2+3->1 step

7=2+2+3=2+5->2 steps

11=2+2+7=3+3+5->2 steps

13=2+11=3+5+5=3+3+7->3 steps

41=2+2+37=3+7+31=5+7+29=5+13+23=5+17+19=11+13+17->6 steps

CROSSREFS

Sequence in context: A093337 A254528 A176044 * A104305 A050506 A155213

Adjacent sequences:  A120394 A120395 A120396 * A120398 A120399 A120400

KEYWORD

nonn

AUTHOR

Robin Garcia, Jul 01 2006

STATUS

approved

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Last modified February 15 20:07 EST 2019. Contains 320138 sequences. (Running on oeis4.)