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.

A066740 Number of distinct partitions of A007504(n) which can be obtained by merging parts in the partition 2+3+5+...+prime(n), where prime(n) is the n-th prime.

Original entry on oeis.org

1, 1, 2, 5, 13, 44, 151, 614, 2446, 11066, 53368, 253927, 1316375, 7213979, 38175696, 213766427
Offset: 0

Views

Author

Naohiro Nomoto, Jan 16 2002

Keywords

Examples

			For n=4, the 13 partitions are 17, 2+15, 3+14, 5+12, 7+10, 8+9, 2+3+12, 2+5+10, 2+7+8, 3+5+9, 3+7+7, 5+5+7, 2+3+5+7. 5+12 and 7+10 can be obtained in two ways each: 5+12 = (5)+(2+3+7) = (2+3)+(5+7), 7+10 = (7)+(2+3+5) = (2+5)+(3+7).
		

Crossrefs

Programs

  • Maple
    b:= proc(n) local p; p:= `if`(n=0, 1, ithprime(n));
          b(n):= `if`(n<2, {[p$n]}, map(x-> [sort([x[], p]),
          seq(sort(subsop(i=x[i]+p, x)), i=1..nops(x))][], b(n-1)))
        end:
    a:= n-> nops(b(n)):
    seq(a(n), n=0..10);  # Alois P. Heinz, May 31 2013
  • Mathematica
    addto[ p_, k_ ] := Module[ {}, lth=Length[ p ]; Union[ Sort/@Append[ Table[ Join[ Take[ p, i-1 ], {p[ [ i ] ]+k}, Take[ p, i-lth ] ], {i, 1, lth} ], Append[ p, k ] ] ] ]; addtolist[ plist_, k_ ] := Union[ Join@@(addto[ #, k ]&/@plist) ]; l[ 0 ]={{}}; l[ n_ ] := l[ n ]=addtolist[ l[ n-1 ], Prime[ n ] ]; a[ n_ ] := Length[ l[ n ] ]

Extensions

Edited by Dean Hickerson, Jan 18 2002
a(14)-a(15) from Sean A. Irvine, Nov 05 2023