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A103273 Number of ways of writing prime(n)-1 in the form prime(i)+prime(j). 0
0, 0, 1, 1, 2, 1, 2, 2, 3, 2, 3, 4, 3, 4, 4, 3, 4, 6, 6, 5, 6, 7, 5, 4, 7, 6, 8, 6, 8, 7, 10, 7, 5, 8, 5, 12, 11, 10, 6, 6, 7, 14, 8, 11, 9, 13, 19, 11, 7, 12, 7, 9, 18, 9, 8, 9, 9, 19, 16, 14, 16, 8, 15, 12, 17, 10, 24, 19, 9, 16, 10, 10, 18, 18, 22, 10, 9, 21, 14, 20, 11, 30, 14, 19, 21, 13, 13 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,5
LINKS
FORMULA
a(n) = A061358(prime(n)-1). - David Wasserman, Oct 08 2005
EXAMPLE
11-1=3+7=5+5, so a(5)=2.
MATHEMATICA
Table[Count[IntegerPartitions[p-1, {2}], _?(AllTrue[#, PrimeQ]&)], {p, Prime[ Range[90]]}] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Sep 09 2019 *)
CROSSREFS
Sequence in context: A078661 A029263 A097575 * A289120 A025066 A060426
KEYWORD
nonn
AUTHOR
Yasutoshi Kohmoto, Jan 27 2005
EXTENSIONS
More terms from David Wasserman, Oct 08 2005
STATUS
approved

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Last modified March 29 08:49 EDT 2024. Contains 371268 sequences. (Running on oeis4.)