A070215 Number of ways to write the n-th prime as a sum of distinct primes.
1, 1, 2, 2, 1, 2, 2, 3, 5, 7, 9, 11, 14, 15, 19, 26, 35, 39, 50, 61, 67, 87, 102, 130, 178, 204, 224, 257, 278, 320, 522, 595, 724, 776, 1064, 1136, 1364, 1634, 1836, 2192, 2601, 2761, 3645, 3863, 4294, 4549, 6262, 8558, 9453, 9964, 11001, 12774, 13438
Offset: 1
Keywords
Examples
With the 10th prime 29, for instance, we have a(10)=7 distinct-prime partitions, viz. 29 = 2 + 3 + 7 + 17 = 2 + 3 + 5 + 19 = 2 + 3 + 11 + 13 = 3 + 7 + 19 = 5 + 7 + 17 = 5 + 11 + 13.
Links
- David A. Corneth, Table of n, a(n) for n = 1..10000 (first 1201 terms from Seth Troisi)
Programs
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Haskell
a070215 = a000586 . a000040 -- Reinhard Zumkeller, Aug 05 2012
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Mathematica
nn = PrimePi[300]; t = CoefficientList[Series[Product[(1 + x^Prime[k]), {k, nn}], {x, 0, Prime[nn]}], x]; t[[1 + Prime[Range[nn]]]] (* T. D. Noe, Nov 13 2013 *)
Formula
a(n) = A000586(prime(n)). - R. J. Mathar, Apr 30 2007
Extensions
More terms from Naohiro Nomoto and Don Reble, May 11 2002
Offset in b-file corrected by N. J. A. Sloane, Aug 31 2009