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 1-9 of 9 results.

A326844 Let y be the integer partition with Heinz number n. Then a(n) is the size of the complement, in the minimal rectangular partition containing the Young diagram of y, of the Young diagram of y.

Original entry on oeis.org

0, 0, 0, 0, 0, 1, 0, 0, 0, 2, 0, 2, 0, 3, 1, 0, 0, 1, 0, 4, 2, 4, 0, 3, 0, 5, 0, 6, 0, 3, 0, 0, 3, 6, 1, 2, 0, 7, 4, 6, 0, 5, 0, 8, 2, 8, 0, 4, 0, 2, 5, 10, 0, 1, 2, 9, 6, 9, 0, 5, 0, 10, 4, 0, 3, 7, 0, 12, 7, 4, 0, 3, 0, 11, 1, 14, 1, 9, 0, 8, 0, 12, 0, 8, 4, 13, 8, 12, 0, 4, 2, 16, 9, 14, 5, 5, 0, 3, 6, 4
Offset: 1

Views

Author

Gus Wiseman, Jul 26 2019

Keywords

Comments

The Heinz number of an integer partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k).

Examples

			The partition with Heinz number 7865 is (6,5,5,3), with diagram:
  o o o o o o
  o o o o o .
  o o o o o .
  o o o . . .
The size of the complement (shown in dots) in a 6 X 4 rectangle is 5, so a(7865) = 5.
		

Crossrefs

Programs

  • Mathematica
    Table[If[n==1,0,With[{y=Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]},Max[y]*Length[y]-Total[y]]],{n,100}]
  • PARI
    A056239(n) = if(1==n, 0, my(f=factor(n)); sum(i=1, #f~, f[i, 2] * primepi(f[i, 1])));
    A061395(n) = if(n>1, primepi(vecmax(factor(n)[, 1])), 0);
    A326844(n) = ((bigomega(n)*A061395(n)) - A056239(n)); \\ Antti Karttunen, Feb 10 2023

Formula

a(n) = A001222(n) * A061395(n) - A056239(n).

Extensions

Data section extended up to term a(100) by Antti Karttunen, Feb 10 2023

A340386 Heinz numbers of integer partitions with an odd number of parts, the greatest of which is odd.

Original entry on oeis.org

2, 5, 8, 11, 17, 20, 23, 30, 31, 32, 41, 44, 45, 47, 50, 59, 66, 67, 68, 73, 75, 80, 83, 92, 97, 99, 102, 103, 109, 110, 120, 124, 125, 127, 128, 137, 138, 149, 153, 154, 157, 164, 165, 167, 170, 176, 179, 180, 186, 188, 191, 197, 200, 207, 211, 227, 230
Offset: 1

Views

Author

Gus Wiseman, Jan 25 2021

Keywords

Comments

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.

Examples

			The sequence of partitions together with their Heinz numbers begins:
      2: (1)             59: (17)           120: (3,2,1,1,1)
      5: (3)             66: (5,2,1)        124: (11,1,1)
      8: (1,1,1)         67: (19)           125: (3,3,3)
     11: (5)             68: (7,1,1)        127: (31)
     17: (7)             73: (21)           128: (1,1,1,1,1,1,1)
     20: (3,1,1)         75: (3,3,2)        137: (33)
     23: (9)             80: (3,1,1,1,1)    138: (9,2,1)
     30: (3,2,1)         83: (23)           149: (35)
     31: (11)            92: (9,1,1)        153: (7,2,2)
     32: (1,1,1,1,1)     97: (25)           154: (5,4,1)
     41: (13)            99: (5,2,2)        157: (37)
     44: (5,1,1)        102: (7,2,1)        164: (13,1,1)
     45: (3,2,2)        103: (27)           165: (5,3,2)
     47: (15)           109: (29)           167: (39)
     50: (3,3,1)        110: (5,3,1)        170: (7,3,1)
		

Crossrefs

Note: Heinz numbers are given in parentheses below.
The case of odd length only is A026424.
The case of odd maximum only is A244991.
Positions of odd terms in A326846.
These partitions are counted by A340385.
The version for factorizations is A340607.
A000009 counts partitions into odd parts (A066208).
A027193 counts partitions of odd length, or of odd maximum.
A061395 gives maximum prime index.
A106529 lists numbers with Omega equal to maximum prime index.
A160786 counts odd-length partitions of odd numbers (A300272).
A339890 counts factorizations of odd length.
A340102 counts odd-length factorizations into odd factors.

Programs

  • Mathematica
    Select[Range[100],OddQ[PrimeOmega[#]*PrimePi[FactorInteger[#][[-1,1]]]]&]

Formula

Intersection of A026424 (odd length) and A244991 (odd maximum).

A326845 Sum times maximum of the integer partition with Heinz number n.

Original entry on oeis.org

0, 1, 4, 2, 9, 6, 16, 3, 8, 12, 25, 8, 36, 20, 15, 4, 49, 10, 64, 15, 24, 30, 81, 10, 18, 42, 12, 24, 100, 18, 121, 5, 35, 56, 28, 12, 144, 72, 48, 18, 169, 28, 196, 35, 21, 90, 225, 12, 32, 21, 63, 48, 256, 14, 40, 28, 80, 110, 289, 21, 324, 132, 32, 6, 54, 40
Offset: 1

Views

Author

Gus Wiseman, Jul 26 2019

Keywords

Comments

The Heinz number of an integer partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k).

Crossrefs

Programs

  • Mathematica
    Table[If[n==1,0,With[{y=Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]},Total[y]*Max[y]]],{n,100}]

Formula

a(n) = A056239(n) * A061395(n).

A359360 Length times minimum part of the integer partition with Heinz number n. Least prime index of n times number of prime indices of n.

Original entry on oeis.org

0, 1, 2, 2, 3, 2, 4, 3, 4, 2, 5, 3, 6, 2, 4, 4, 7, 3, 8, 3, 4, 2, 9, 4, 6, 2, 6, 3, 10, 3, 11, 5, 4, 2, 6, 4, 12, 2, 4, 4, 13, 3, 14, 3, 6, 2, 15, 5, 8, 3, 4, 3, 16, 4, 6, 4, 4, 2, 17, 4, 18, 2, 6, 6, 6, 3, 19, 3, 4, 3, 20, 5, 21, 2, 6, 3, 8, 3, 22, 5, 8, 2
Offset: 1

Views

Author

Gus Wiseman, Dec 28 2022

Keywords

Comments

The Heinz number of an integer partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k). A prime index of n is a number m such that prime(m) divides n.

Examples

			The partition with Heinz number 7865 is (6,5,5,3), so a(7865) = 4*3 = 12.
		

Crossrefs

Difference of A056239 and A359358.
The opposite version is A326846.
A055396 gives minimum prime index, maximum A061395.
A112798 list prime indices, length A001222, sum A056239.
A243055 subtracts the least prime index from the greatest.
A358195 gives Heinz numbers of rows of A358172, even bisection A241916.

Programs

  • Mathematica
    Table[PrimeOmega[n]*PrimePi[FactorInteger[n][[1,1]]],{n,100}]
  • PARI
    a(n) = if (n==1, 0, my(f=factor(n)); bigomega(f)*primepi(f[1, 1])); \\ Michel Marcus, Dec 28 2022

Formula

a(n) = A001222(n) * A055396(n).

A331297 Lexicographically earliest infinite sequence such that a(i) = a(j) => A263297(i) = A263297(j) and A325225(i) = A325225(j) for all i, j.

Original entry on oeis.org

1, 2, 3, 3, 4, 5, 6, 4, 5, 7, 8, 7, 9, 10, 7, 6, 11, 7, 12, 13, 10, 14, 15, 10, 7, 16, 7, 17, 18, 13, 19, 8, 14, 20, 10, 10, 21, 22, 16, 17, 23, 17, 24, 25, 13, 26, 27, 14, 10, 13, 20, 28, 29, 10, 14, 30, 22, 31, 32, 17, 33, 34, 17, 9, 16, 25, 35, 36, 26, 17, 37, 14, 38, 39, 13, 40, 14, 28, 41, 25, 10, 42, 43, 30, 20, 44, 31, 45, 46, 17, 16, 47, 34, 48, 22, 16, 49, 17, 25, 17
Offset: 1

Views

Author

Antti Karttunen, Jan 18 2020

Keywords

Comments

Restricted growth sequence transform of the unordered pair [A001222(n), A061395(n)].

Crossrefs

Programs

  • PARI
    up_to = 65537;
    rgs_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(om,invec[i]), my(pp = mapget(om, invec[i])); outvec[i] = outvec[pp] , mapput(om,invec[i],i); outvec[i] = u; u++ )); outvec; };
    A061395(n) = if(1==n, 0, primepi(vecmax(factor(n)[, 1])));
    Aux331297(n) = { my(a=bigomega(n),b=A061395(n)); [min(a,b),max(a,b)]; };
    Aux331297(n) = Set([bigomega(n),A061395(n)]); \\ Alternatively.
    v331297 = rgs_transform(vector(up_to, n, Aux331297(n)));
    A331297(n) = v331297[n];

Formula

For all i, j:
A331170(i) = A331170(j) => a(i) = a(j),
A331298(i) = A331298(j) => a(i) = a(j),
A331299(i) = A331299(j) => a(i) = a(j),
a(i) = a(j) => A326846(i) = A326846(j).

A359358 Let y be the integer partition with Heinz number n. Then a(n) is the size of the Young diagram of y after removing a rectangle of the same length as y and width equal to the smallest part of y.

Original entry on oeis.org

0, 0, 0, 0, 0, 1, 0, 0, 0, 2, 0, 1, 0, 3, 1, 0, 0, 2, 0, 2, 2, 4, 0, 1, 0, 5, 0, 3, 0, 3, 0, 0, 3, 6, 1, 2, 0, 7, 4, 2, 0, 4, 0, 4, 1, 8, 0, 1, 0, 4, 5, 5, 0, 3, 2, 3, 6, 9, 0, 3, 0, 10, 2, 0, 3, 5, 0, 6, 7, 5, 0, 2, 0, 11, 2, 7, 1, 6, 0, 2, 0, 12, 0, 4, 4, 13
Offset: 1

Views

Author

Gus Wiseman, Dec 27 2022

Keywords

Comments

The Heinz number of an integer partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k).

Examples

			The partition with Heinz number 7865 is (6,5,5,3), which has the following diagram. The 3 X 4 rectangle is shown in dots.
  . . . o o o
  . . . o o
  . . . o o
  . . .
The size of the complement is 7, so a(7865) = 7.
		

Crossrefs

The opposite version is A326844.
Row sums of A356958 are a(n) + A001222(n) - 1, Heinz numbers A246277.
A055396 gives minimum prime index, maximum A061395.
A112798 list prime indices, sum A056239.
A243055 subtracts the least prime index from the greatest.
A326846 = size of the smallest rectangle containing the prime indices of n.
A358195 gives Heinz numbers of rows of A358172, even bisection A241916.

Programs

  • Mathematica
    Table[If[n==1,0,With[{q=Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]},Total[q]-q[[1]]*Length[q]]],{n,100}]

Formula

a(n) = A056239(n) - A001222(n) * A055396(n).
a(n) = A056239(n) - A359360(n).

A359362 a(n) = (A001222(n) + 1) * A056239(n), where A001222 counts prime indices and A056239 adds them up.

Original entry on oeis.org

0, 2, 4, 6, 6, 9, 8, 12, 12, 12, 10, 16, 12, 15, 15, 20, 14, 20, 16, 20, 18, 18, 18, 25, 18, 21, 24, 24, 20, 24, 22, 30, 21, 24, 21, 30, 24, 27, 24, 30, 26, 28, 28, 28, 28, 30, 30, 36, 24, 28, 27, 32, 32, 35, 24, 35, 30, 33, 34, 35, 36, 36, 32, 42, 27, 32, 38
Offset: 1

Views

Author

Gus Wiseman, Dec 31 2022

Keywords

Comments

A prime index of n is a number m such that prime(m) divides n. The multiset of prime indices of n is row n of A112798.

Crossrefs

A055396 gives minimum prime index, maximum A061395.
A112798 list prime indices, length A001222, sum A056239.

Programs

  • Mathematica
    primeMS[n_]:=If[n==1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]];
    Table[(PrimeOmega[n]+1)*Total[primeMS[n]],{n,30}]
  • Python
    from sympy import primepi, factorint
    def A359362(n): return (sum((f:=factorint(n)).values())+1)*sum(primepi(p)*e for p, e in f.items()) # Chai Wah Wu, Jan 01 2023

Formula

a(n) = (k + 1) * m, where m and k are the sum and length of the integer partition with Heinz number n.
a(n) = 2*A304818(n) - A261079(n).

A331298 Lexicographically earliest infinite sequence such that a(i) = a(j) => A001222(i) = A001222(j) and A061395(i) = A061395(j) for all i, j.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 6, 9, 10, 11, 12, 13, 9, 14, 15, 11, 16, 17, 13, 18, 19, 20, 9, 21, 11, 22, 23, 17, 24, 25, 18, 26, 13, 20, 27, 28, 21, 29, 30, 22, 31, 32, 17, 33, 34, 35, 13, 17, 26, 36, 37, 20, 18, 38, 28, 39, 40, 29, 41, 42, 22, 43, 21, 32, 44, 45, 33, 22, 46, 35, 47, 48, 17, 49, 18, 36, 50, 51, 20, 52, 53, 38, 26, 54, 39, 55, 56, 29, 21, 57, 42, 58, 28, 59, 60, 22, 32, 29
Offset: 1

Views

Author

Antti Karttunen, Jan 18 2020

Keywords

Comments

Restricted growth sequence transform of the ordered pair [A001222(n), A061395(n)].
For all i, j:
A318891(i) = A318891(j) => a(i) = a(j),
a(i) = a(j) => A331297(i) = A331297(j) => A326846(i) = A326846(j),
a(i) = a(j) => A331281(i) = A331281(j),
a(i) = a(j) => A331282(i) = A331282(j).

Crossrefs

Programs

  • PARI
    up_to = 65537;
    rgs_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(om,invec[i]), my(pp = mapget(om, invec[i])); outvec[i] = outvec[pp] , mapput(om,invec[i],i); outvec[i] = u; u++ )); outvec; };
    A061395(n) = if(1==n, 0, primepi(vecmax(factor(n)[, 1])));
    Aux331298(n) = [bigomega(n),A061395(n)];
    v331298 = rgs_transform(vector(up_to, n, Aux331298(n)));
    A331298(n) = v331298[n];

A362047 Numbers whose prime indices satisfy: (maximum) - (minimum) = (mean).

Original entry on oeis.org

10, 30, 39, 90, 98, 99, 100, 115, 259, 270, 273, 300, 490, 495, 517, 663, 665, 793, 810, 900, 1000, 1083, 1241, 1421, 1495, 1521, 1691, 1911, 2058, 2079, 2125, 2145, 2369, 2430, 2450, 2475, 2662, 2700, 2755, 2821, 3000, 3277, 4247, 4495, 4921, 5587, 5863, 6069
Offset: 1

Views

Author

Gus Wiseman, Apr 11 2023

Keywords

Comments

A prime index of n is a number m such that prime(m) divides n. The multiset of prime indices of n is row n of A112798.

Examples

			The terms together with their prime indices begin:
      10: {1,3}
      30: {1,2,3}
      39: {2,6}
      90: {1,2,2,3}
      98: {1,4,4}
      99: {2,2,5}
     100: {1,1,3,3}
     115: {3,9}
     259: {4,12}
     270: {1,2,2,2,3}
     273: {2,4,6}
     300: {1,1,2,3,3}
The prime indices of 490 are {1,3,4,4}, with minimum 1, maximum 4, and mean 3, and 4-1 = 3, so 490 is in the sequence.
		

Crossrefs

Partitions of this type are counted by A361862.
For minimum instead of mean we have A361908, counted by A118096.
A055396 gives minimum prime index, A061395 maximum.
A112798 list prime indices, length A001222, sum A056239.
A243055 subtracts the least prime index from the greatest.
A326844 gives the diagram complement size of Heinz partition.

Programs

  • Mathematica
    prix[n_]:=If[n==1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]];
    Select[Range[100],Max@@prix[#]-Min@@prix[#]==Mean[prix[#]]&]
  • Python
    from itertools import count, islice
    from sympy import primepi, factorint
    def A362047_gen(startvalue=2): # generator of terms >= startvalue
        return filter(lambda n:(primepi(max(f:=factorint(n)))-primepi(min(f)))*sum(f.values())==sum(primepi(i)*j for i, j in f.items()),count(max(startvalue,2)))
    A362047_list = list(islice(A362047_gen(),20)) # Chai Wah Wu, Apr 13 2023

Formula

A359360(a(n)) = A326844(a(n)).
A243055(a(n)) = A061395(a(n)) - A055396(a(n))
= A326567(a(n))/A326568(a(n))
= A056239(a(n))/A001222(a(n)).
Showing 1-9 of 9 results.