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.

A073335 Total number of prime power parts in all partitions of n.

Original entry on oeis.org

0, 1, 2, 5, 8, 15, 23, 39, 58, 89, 128, 189, 264, 375, 515, 713, 960, 1301, 1726, 2298, 3011, 3948, 5113, 6625, 8492, 10880, 13825, 17545, 22108, 27823, 34800, 43465, 54003, 66983, 82709, 101960, 125180, 153432, 187397, 228490, 277707, 336972
Offset: 1

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Author

Vladeta Jovovic, Aug 22 2002

Keywords

Examples

			a(4)=5 because in all partitions of 4 we have 5 powers of primes (shown between parentheses): (4), (3)1, (2)(2), (2)11, 1111.
		

Crossrefs

Programs

  • Maple
    with(numtheory): with(combinat): a:= n-> add(bigomega(k)*numbpart(n-k), k=1..n): seq(a(n), n=1..46); # Emeric Deutsch, Feb 26 2005
  • Mathematica
    Table[Sum[PrimeOmega[k]*PartitionsP[n - k], {k, 1, n}], {n, 1, 50}] (* G. C. Greubel, May 05 2017 *)
  • PARI
    a(n) = sum(k=1, n, bigomega(k)*numbpart(n-k)); \\ Michel Marcus, May 05 2017

Formula

a(n) = Sum_{k=1..n} bigomega(k)*numbpart(n-k).
G.f.: Sum_{i>=2} floor(1/omega(i))*x^i/(1 - x^i) / Product_{j>=1} (1 - x^j), where omega() is the number of distinct prime factors (A001221). - Ilya Gutkovskiy, Jan 24 2017

Extensions

More terms from Emeric Deutsch, Feb 26 2005