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.

Showing 1-8 of 8 results.

A163098 a(n) = A127219(n)/2.

Original entry on oeis.org

1, 4, 5, 11, 13, 14, 15, 17, 20, 21, 23, 25, 29, 31, 32, 33, 35, 37, 39, 40, 42, 43, 47, 48, 49, 50, 53, 54, 55, 56, 58, 60, 61, 62, 63, 64, 65, 68, 71, 77, 79, 80, 85, 87, 88, 90, 92, 99, 100, 103, 112, 114, 115, 118, 123, 124, 128, 129, 130, 131, 132, 134, 137, 139, 140
Offset: 1

Views

Author

Omar E. Pol, Aug 09 2009

Keywords

Crossrefs

Programs

  • Maple
    Contribution from R. J. Mathar, Oct 09 2010: (Start)
    A127219 := proc(n) option remember; if n = 1 then 2; else for a from procname(n-1)+2 by 2 do if type(combinat[numbpart](a) ,'even') then return a; fi; end do; fi ; end proc:
    A163098 := proc(n) A127219(n)/2 ; end proc;
    seq(A163098(n),n=1..100) ; (End)

Extensions

More terms from R. J. Mathar, Oct 09 2010

A154798 Even partition numbers of even numbers.

Original entry on oeis.org

2, 22, 42, 1002, 2436, 3718, 5604, 12310, 37338, 53174, 105558, 204226, 715220, 1300156, 1741630, 2323520, 4087968, 7089500, 12132164, 15796476, 26543660, 34262962, 92669720, 118114304, 150198136, 190569292, 384276336, 483502844
Offset: 1

Views

Author

Omar E. Pol, Jan 26 2009

Keywords

Comments

Even numbers in A058696.

Crossrefs

Programs

  • Maple
    aa:= proc(n, i) if n=0 then 1 elif n<0 or i=0 then 0 else aa(n,i):= aa(n, i-1) +aa(n-i, i) fi end: a:= proc(n) local k; if n>1 then a(n-1) fi; for k from `if`(n=1, 0, b(n-1)+2) by 2 while irem(aa(k, k), 2)=1 do od; b(n):= k; aa(k, k) end: seq(a(n), n=1..40); # Alois P. Heinz, Jul 28 2009
  • Mathematica
    Select[Table[PartitionsP[n], {n, 0, 200, 2}], EvenQ] (* Jean-François Alcover, Aug 28 2015 *)
  • PARI
    select(x->!(x%2), vector(80, n, numbpart(2*n))) \\ Michel Marcus, Aug 28 2015

Extensions

More terms from Alois P. Heinz, Jul 28 2009

A163097 Even numbers with an odd number of partitions.

Original entry on oeis.org

0, 4, 6, 12, 14, 16, 18, 20, 24, 32, 36, 38, 44, 48, 52, 54, 56, 60, 68, 72, 76, 82, 88, 90, 92, 102, 104, 114, 118, 132, 134, 138, 140, 144, 146, 148, 150, 152, 156, 162, 164, 166, 168, 172, 178, 182, 186, 188, 190, 192, 194, 196, 202, 204, 208, 210, 212, 214, 216
Offset: 1

Views

Author

Omar E. Pol, Aug 09 2009

Keywords

Crossrefs

Programs

  • Mathematica
    Select[2*Range[0,150],OddQ[PartitionsP[#]]&] (* Harvey P. Dale, Nov 13 2013 *)

Extensions

More terms from Sean A. Irvine, Oct 26 2009

A194798 Numbers n having the same parity as the number of partitions of n.

Original entry on oeis.org

1, 2, 3, 5, 7, 8, 10, 13, 17, 22, 23, 26, 28, 29, 30, 33, 34, 35, 37, 39, 40, 41, 42, 43, 46, 49, 50, 51, 53, 58, 61, 62, 63, 64, 66, 67, 69, 70, 71, 73, 74, 77, 78, 80, 81, 83, 84, 85, 86, 87, 89, 91, 93, 94, 95, 96, 98, 99, 100, 105, 106, 107, 108, 110, 111
Offset: 1

Views

Author

Omar E. Pol, Jan 29 2012

Keywords

Comments

Odd positive integers with an odd number of partitions and even positive integers with an even number of partitions. - Omar E. Pol, Mar 17 2012
Union of A067567 and A127219. Note that the union of A163096 and A163097 gives A209920 and the union of A209920 and this sequence gives A001477. - Omar E. Pol, Mar 22 2012

Examples

			10 is in the sequence because the number of partitions of 10 is equal to 42 and both 10 and 42 have the same parity.
		

Crossrefs

Programs

  • Maple
    with(combinat):
    a:= proc(n) option remember; local k;
          for k from 1+`if`(n=1, 0, a(n-1))
          while irem(k+numbpart(k), 2)=1 do od; k
        end:
    seq(a(n), n=1..80); # Alois P. Heinz, Mar 16 2012
  • Mathematica
    Select[Range[200], Mod[PartitionsP[#] - #, 2] == 0 &] (* T. D. Noe, Mar 16 2012 *)

Extensions

More terms from Alois P. Heinz, Mar 16 2012

A209920 Numbers n having distinct parity as the number of partitions of n.

Original entry on oeis.org

0, 4, 6, 9, 11, 12, 14, 15, 16, 18, 19, 20, 21, 24, 25, 27, 31, 32, 36, 38, 44, 45, 47, 48, 52, 54, 55, 56, 57, 59, 60, 65, 68, 72, 75, 76, 79, 82, 88, 90, 92, 97, 101, 102, 103, 104, 109, 113, 114, 117, 118, 125, 129, 131, 132, 133, 134, 135, 137, 138, 140
Offset: 1

Views

Author

Omar E. Pol, Mar 16 2012

Keywords

Comments

Odd positive integers with an even number of partitions and nonnegative even integers with an odd number of partitions. Union of A163097 and A163096. Note that the union of A067567 and A127219 gives A194798 and the union of A194798 and this sequence gives A001477.

Examples

			4 is in the sequence because the number of partitions of 4 is equal to 5 and the parity of 4 is distinct to the parity of 5 because 4 is even and 5 is odd.
9 is in the sequence because the number of partitions of 9 is equal to 30 and the parity of 9 is distinct to the parity of 30 because 9 is odd and 30 is even.
		

Crossrefs

A209658 Partition numbers p(n) having the same parity as n.

Original entry on oeis.org

1, 2, 3, 7, 15, 22, 42, 101, 297, 1002, 1255, 2436, 3718, 4565, 5604, 10143, 12310, 14883, 21637, 31185, 37338, 44583, 53174, 63261, 105558, 173525, 204226, 239943, 329931, 715220, 1121505, 1300156, 1505499, 1741630, 2323520, 2679689, 3554345
Offset: 1

Views

Author

Omar E. Pol, Mar 22 2012

Keywords

Comments

Union of A154795 and A154798. The union of A209659 and this sequence gives A000041.

Crossrefs

A209659 Partition numbers p(n) having opposite parity of n.

Original entry on oeis.org

1, 5, 11, 30, 56, 77, 135, 176, 231, 385, 490, 627, 792, 1575, 1958, 3010, 6842, 8349, 17977, 26015, 75175, 89134, 124754, 147273, 281589, 386155, 451276, 526823, 614154, 831820, 966467, 2012558, 3087735, 5392783, 8118264, 9289091, 13848650
Offset: 1

Views

Author

Omar E. Pol, Mar 22 2012

Keywords

Comments

Union of A154797 and A154796. The union of this sequence and A209658 gives A000041.

Crossrefs

A127700 Numbers n such that partition number of n^2 is even.

Original entry on oeis.org

3, 5, 8, 10, 16, 20, 21, 23, 26, 28, 30, 39, 41, 43, 45, 46, 47, 48, 49, 50, 51, 56, 58, 59, 63, 66, 68, 70, 71, 73, 76, 78, 80, 82, 84, 85, 86, 87, 88, 92, 93, 95, 96, 97, 100, 102, 103, 111, 112, 113, 115, 117, 120, 121, 122, 123, 125, 127, 129, 131, 134, 135, 137
Offset: 1

Views

Author

Zak Seidov, Apr 03 2007

Keywords

Crossrefs

Programs

  • Mathematica
    Select[Range[200],EvenQ[PartitionsP[ #^2]]&]

Formula

A000041(n^2) is even.
Showing 1-8 of 8 results.