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A073685 Group the composite numbers so that the sum of each group is a prime: (4, 6, 8, 9, 10), (12, 14, 15), (16, 18, 20, 21, 22), (24, 25, 26, 27, 28, 30, 32, 33, 34, 35, 36, 38, 39, 40, 42, 44, 45, 46, 48, 49, 50, 51, 52, 54, 55), ...; sequence gives number of terms in each group. 2
5, 3, 5, 25, 2, 5, 2, 2, 5, 8, 6, 4, 2, 3, 5, 2, 2, 18, 2, 35, 8, 21, 2, 2, 2, 6, 17, 3, 6, 9, 2, 8, 11, 7, 5, 15, 27, 3, 4, 2, 18, 3, 7, 2, 2, 22, 4, 12, 27, 31, 2, 16, 16, 5, 2, 16, 2, 21, 7, 12, 2, 2, 4, 22, 8, 10, 2, 7, 2, 2, 8, 7, 8, 2, 4, 22, 2, 30, 8, 21, 2, 3, 28, 24, 4, 10, 7, 4, 6, 3, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..91.

MATHEMATICA

t1 = Rest[Select[Range[970], ! PrimeQ[#] &]]; t = {}; s = c = 0; Do[s += i; c += 1; If[PrimeQ[s], AppendTo[t, c]; s = c = 0], {i, t1}]; t (* Jayanta Basu, Jul 07 2013 *)

CROSSREFS

Cf. A073686, A073687.

Sequence in context: A144386 A256787 A265782 * A019212 A201928 A021655

Adjacent sequences:  A073682 A073683 A073684 * A073686 A073687 A073688

KEYWORD

nonn

AUTHOR

Amarnath Murthy, Aug 11 2002

EXTENSIONS

More terms from Lior Manor Aug 13 2002

STATUS

approved

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Last modified January 21 17:55 EST 2022. Contains 350479 sequences. (Running on oeis4.)