cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A070215 Number of ways to write the n-th prime as a sum of distinct primes.

Original entry on oeis.org

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

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Author

Lekraj Beedassy, May 07 2002

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.
		

Crossrefs

Cf. A000586, A056768 (parts may repeat).

Programs

  • Haskell
    a070215 = a000586 . a000040  -- Reinhard Zumkeller, Aug 05 2012
  • 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