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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 1-3 of 3 results.

A352873 Heinz numbers of integer partitions with nonnegative crank, counted by A064428.

Original entry on oeis.org

1, 3, 5, 6, 7, 9, 10, 11, 13, 14, 15, 17, 18, 19, 21, 22, 23, 25, 26, 27, 29, 30, 31, 33, 34, 35, 37, 38, 39, 41, 42, 43, 45, 46, 47, 49, 50, 51, 53, 54, 55, 57, 58, 59, 61, 62, 63, 65, 66, 67, 69, 70, 71, 73, 74, 75, 77, 78, 79, 81, 82, 83, 85, 86, 87, 89, 90
Offset: 1

Views

Author

Gus Wiseman, Apr 09 2022

Keywords

Comments

First differs from A042968, A059557, and A195291 in lacking 2 and having 100.
The Heinz number of a partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k). This gives a bijective correspondence between positive integers and integer partitions.
The crank of a partition p is defined to be (i) the largest part of p if there is no 1 in p and (ii) (the number of parts larger than the number of 1's) minus (the number of 1's). [Definition copied from A342192; see A064428 for a different wording.]

Examples

			The terms together with their prime indices begin:
     1: ()         22: (5,1)      42: (4,2,1)
     3: (2)        23: (9)        43: (14)
     5: (3)        25: (3,3)      45: (3,2,2)
     6: (2,1)      26: (6,1)      46: (9,1)
     7: (4)        27: (2,2,2)    47: (15)
     9: (2,2)      29: (10)       49: (4,4)
    10: (3,1)      30: (3,2,1)    50: (3,3,1)
    11: (5)        31: (11)       51: (7,2)
    13: (6)        33: (5,2)      53: (16)
    14: (4,1)      34: (7,1)      54: (2,2,2,1)
    15: (3,2)      35: (4,3)      55: (5,3)
    17: (7)        37: (12)       57: (8,2)
    18: (2,2,1)    38: (8,1)      58: (10,1)
    19: (8)        39: (6,2)      59: (17)
    21: (4,2)      41: (13)       61: (18)

Crossrefs

* = unproved
These partitions are counted by A064428.
The case of zero crank is A342192, counted by A064410.
The case of positive crank is A352874.
A000700 counts self-conjugate partitions, ranked by A088902.
A001222 counts prime indices, distinct A001221.
*A001522 counts partitions with a fixed point, ranked by A352827.
A056239 adds up prime indices, row sums of A112798 and A296150.
*A064428 counts partitions without a fixed point, ranked by A352826.
A115720 and A115994 count partitions by their Durfee square.
A122111 represents partition conjugation using Heinz numbers.
A238394 counts reversed partitions without a fixed point, ranked by A352830.
Cf. A065770, A093641, A118199, A188674, A252464, A257990, A325163, A325169, A344609, A352828, A352831.

Programs

  • Mathematica
    ck[y_]:=With[{w=Count[y,1]},If[w==0,Max@@y,Count[y,_?(#>w&)]-w]];
Select[Range[100],ck[Reverse[Flatten[Cases[FactorInteger[#],{p_,k_}:>Table[PrimePi[p],{k}]]]]]>=0&]

Formula

Union of A352874 and A342192.

A059558 Beatty sequence for 1 + 1/gamma^2.

Original entry on oeis.org

4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52, 56, 60, 64, 68, 72, 76, 80, 84, 88, 92, 96, 100, 104, 108, 112, 116, 120, 124, 128, 132, 136, 140, 144, 148, 152, 156, 160, 164, 168, 172, 176, 180, 184, 188, 192, 196, 200, 204, 208, 212, 216, 220, 224, 228
Offset: 1

Views

Author

Mitch Harris, Jan 22 2001

Keywords

Comments

The first term where this sequence breaks the progression a(n) = a(n-1) + 4 is a(715) = 2861. - Max Alekseyev, Mar 03 2007

Links

Crossrefs

Beatty complement is A059557.
Cf. A001620, A098907, A155969.

Programs

  • Mathematica
    Floor[Range[100]*(1 + 1/EulerGamma^2)] (* Paolo Xausa, Jul 05 2024 *)
  • PARI
    { default(realprecision, 100); b=1 + 1/Euler^2; for (n = 1, 2000, write("b059558.txt", n, " ", floor(n*b)); ) } \\ Harry J. Smith, Jun 28 2009

Formula

a(n) = floor(n*(1+1/gamma^2)) where 1+1/gamma^2= 1+A098907^2 = 4.00139933... - R. J. Mathar, Sep 29 2023

Extensions

Removed incorrect comment, Joerg Arndt, Nov 14 2014

A250254 First row of spectral array W(gamma^2+1).

Original entry on oeis.org

1, 4, 5, 16, 21, 64, 85, 256, 341, 1024, 1365, 4097, 5462, 16393, 21854, 65594, 87448, 262467, 349915, 1050235, 1400150, 4202409, 5602558, 16815516
Offset: 1

Views

Author

Colin Barker, Nov 15 2014

Keywords

Comments

Gamma is Euler's (or Euler-Mascheroni) constant.

Links

Crossrefs

Cf. A001620 (Gamma), A059557 (Corresponding Beatty sequence), A250253, A250255.

Programs

  • PARI
    \\ Row i of the generalized Wythoff array W(h),
\\   where h is an irrational number between 1 and 2,
\\   and m is the number of terms in the vectors a and b.
row(h, i, m) = {
  if(h<=1 || h>=2, print("Invalid value for h"); return);
  my(
    a=vector(m, n, floor(n*h)),
    b=vector(m, n, floor(n*h/(h-1))),
    w=[a[a[i]], b[a[i]]],
    j=3
  );
  while(1,
    if(j%2==1,
      if(w[j-1]<=#a, w=concat(w, a[w[j-1]]), return(w))
    ,
      if(w[j-2]<=#b, w=concat(w, b[w[j-2]]), return(w))
    );
    j++
  )
}
allocatemem(10^9)
row(Euler^2+1, 1, 10^7)
Showing 1-3 of 3 results.

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