A064553 -id:A064553 - cp's OEIS frontend

A080688 Resort the index of A064553 using A080444 and maintaining ascending order within each grouping: seen as a triangle read by rows, the n-th row contains the A001055(n) numbers m with A064553(m)=n.

1, 2, 3, 4, 5, 7, 6, 11, 13, 8, 10, 17, 9, 19, 14, 23, 29, 12, 15, 22, 31, 37, 26, 41, 21, 43, 16, 20, 25, 34, 47, 53, 18, 33, 38, 59, 61, 28, 35, 46, 67, 39, 71, 58, 73, 79, 24, 30, 44, 51, 55, 62, 83, 49, 89, 74, 97, 27, 57, 101, 52, 65, 82

Offset: 1

Alford Arnold, Mar 23 2003

The number 12 can be written as 3*2*2, 4*3, 6*2 and 12 corresponding to each of the four values (12,15,22,31) in the example. Note that A001055(12) = 4. Since A001055(n) depends only on the least prime signature, the values 1,2,4,6,8,12,16,24,30,32,36,... A025487 are of special interest when counting multisets. (see for example, A035310 and A035341).
A064553(T(n,k)) = A080444(n,k) = n for k=1..A001055(n); T(n,1) = A064554(n); T(n,A001055(n)) = A064554(n). - Reinhard Zumkeller, Oct 01 2012
Row n is the sorted list of shifted Heinz numbers of factorizations of n into factors > 1, where the shifted Heinz number of a factorization (y_1, ..., y_k) is prime(y_1 - 1) * ... * prime(y_k - 1). - Gus Wiseman, Sep 05 2018

			a(18),a(19),a(20) and a(21) are 12,15,22 and 31 because A064553(12,15,22,31) = (12,12,12,12) similarly, A064553(36,45,66,76,93,95,118,121,149) = (36,36,36,36,36,36,36,36,36)
From _Gus Wiseman_, Sep 05 2018: (Start)
Triangle begins:
   1
   2
   3
   4  5
   7
   6 11
  13
   8 10 17
   9 19
  14 23
  29
  12 15 22 31
  37
  26 41
  21 43
  16 20 25 34 47
Corresponding triangle of factorizations begins:
  (),
  (2),
  (3),
  (2*2), (4),
  (5),
  (2*3), (6),
  (7),
  (2*2*2), (2*4), (8),
  (3*3), (9),
  (2*5), (10),
  (11),
  (2*2*3), (3*4), (2*6), (12).
(End)

Reinhard Zumkeller, Rows n = 1..1000 of triangle, flattened

Cf. A001055, A025487, A035310, A035341, A064553, A080444.

Cf. A007716, A056239, A162247, A215366, A275024, A317144, A317145, A318871.

a080688 n k = a080688_row n !! (k-1)
a080688_row n = map (+ 1) $ take (a001055 n) $
                elemIndices n $ map fromInteger a064553_list
a080688_tabl = map a080688_row [1..]
a080688_list = concat a080688_tabl
-- Reinhard Zumkeller, Oct 01 2012

facs[n_]:=If[n<=1,{{}},Join@@Table[(Prepend[#1,d]&)/@Select[facs[n/d],Min@@#1>=d&],{d,Rest[Divisors[n]]}]];
Table[Sort[Table[Times@@Prime/@(f-1),{f,facs[n]}]],{n,20}] (* Gus Wiseman, Sep 05 2018 *)

More terms from Sean A. Irvine, Oct 05 2011

Keyword tabf added and definition complemented accordingly by Reinhard Zumkeller, Oct 01 2012

A064554 a(n) = Min {k | A064553(k) = n}.

Original entry on oeis.org

1, 2, 3, 4, 7, 6, 13, 8, 9, 14, 29, 12, 37, 26, 21, 16, 53, 18, 61, 28, 39, 58, 79, 24, 49, 74, 27, 52, 107, 42, 113, 32, 87, 106, 91, 36, 151, 122, 111, 56, 173, 78, 181, 116, 63, 158, 199, 48, 169, 98, 159, 148, 239, 54, 203, 104, 183, 214, 271, 84, 281, 226, 117, 64

Offset: 1

Reinhard Zumkeller, Sep 21 2001

nonn

A064553(a(n)) = n and A064553(a(k)) <> k for k < a(n). For prime p, a(p)=prime(p-1), which is sequence A055003. - T. D. Noe, Dec 12 2004
a(n) is not multiplicative because a(7*13) = a(91) = 463, but a(7)*a(13) = 13*37 = 481 and 91 is the smallest possible such n. - Christian G. Bower, May 19 2005
a(n) = A080688(n,1). - Reinhard Zumkeller, Oct 01 2012
Minimal shifted Heinz number of a factorization of n, where the shifted Heinz number of a factorization (y_1, ..., y_k) is prime(y_1 - 1) * ... * prime(y_k - 1). - Gus Wiseman, Sep 05 2018

T. D. Noe, Table of n, a(n) for n = 1..8000
T. D. Noe, Plot of A064554

Cf. A064555, A001055, A064553.
Cf. A055003 (prime(prime(n)-1)).
Cf. A007716, A056239, A162247, A215366, A246868, A318871.

a064554 = head . a080688_row  -- Reinhard Zumkeller, Oct 01 2012

facs[n_]:=If[n<=1,{{}},Join@@Table[(Prepend[#1,d]&)/@Select[facs[n/d],Min@@#1>=d&],{d,Rest[Divisors[n]]}]];
Table[Min[Times@@Prime/@(#-1)&/@facs[n]],{n,100}] (* Gus Wiseman, Sep 05 2018 *)

A064555 a(n) = max { k | A064553(k) = n }.

Original entry on oeis.org

1, 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 319, 317

Offset: 1

Reinhard Zumkeller, Sep 21 2001

a(n+1) = A000040(n) for 1 < n < 66, but A000040(65) = 313 <> 319 = 11*29 = a(66).
In the plot, the lowest line corresponds to the cases when a(n)=prime(n-1). - T. D. Noe, Dec 12 2004
a(n) = A080688(n,A001055(n)). - Reinhard Zumkeller, Oct 01 2012

T. D. Noe, Table of n, a(n) for n = 1..8000

Cf. A064554, A001055, A064553, A000040.

a064555 = last . a080688_row  -- Reinhard Zumkeller, Oct 01 2012

(* b = A064553 *) nmax = 67; b[1] = 1; b[p_?PrimeQ] := b[p] = PrimePi[p] + 1; b[n_] := b[n] = b[p = FactorInteger[n][[1, 1]]]*b[n/p]; bb = Table[{k, b[k]}, {k, 1, 4*Prime[nmax]}]; A064555 = Max[#[[All, 1]]]& /@ Split[ Sort[bb, #1[[2]] < #2[[2]] &], #1[[2]] == #2[[2]]&]; a[n_] := A064555[[n]]; Table[a[n], {n, 1, nmax}] (* Jean-François Alcover, Sep 04 2012 *)

A064553(a(n)) = n and A064553(a(k)) <> k for k > a(n).

A064557 a(n) = # { p | A064553(k) = p prime and k <= n}.

Original entry on oeis.org

0, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9

Offset: 1

Reinhard Zumkeller, Sep 21 2001

nonn

Primes occur in A064553 in natural order but less dense.

A000720, A064553.

A064558 a(n) = A064553(A064553(n)).

Original entry on oeis.org

1, 2, 3, 4, 4, 6, 4, 8, 9, 8, 6, 12, 5, 8, 12, 16, 8, 18, 9, 16, 12, 12, 8, 24, 16, 10, 27, 16, 6, 24, 12, 32, 18, 16, 16, 36, 7, 18, 15, 32, 10, 24, 12, 24, 36, 16, 16, 48, 16, 32, 24, 20, 8, 54, 24, 32, 27, 12, 18, 48, 9, 24, 36, 64, 20, 36, 16, 32, 24, 32, 15, 72, 12, 14, 48, 36

Offset: 1

Reinhard Zumkeller, Sep 21 2001

b[n_] := Product[{p, e} = pe; (PrimePi[p] + 1)^e, {pe, FactorInteger[n]}];
a[n_] := b[b[n]];
Array[a, 100] (* Jean-François Alcover, Nov 21 2021 *)

A064600 a(n) indicates the position of 5 after n iterations of A064553.

Original entry on oeis.org

5, 7, 13, 37, 151, 863, 6689, 67139, 843377, 12903181

Offset: 0

Reinhard Zumkeller, Sep 22 2001

Iterating A064553 spreads the primes further and further apart, although 2 and 3 are fixed. For k < a(n) the n-th iteration of A064553 equals A003586.

			a(3) = 37 as A064553(A064553(A064553(37))) = A064553(A064553(13)) = A064553(7) = 5.

Sean A. Irvine, Java program (github)

Cf. A064558, A000040, A064553, A003586, A064557, A064601.

a(0) = 5 and a(n) = A000040(a(n - 1) - 1) for n > 0.

a(9) from Sean A. Irvine, Jul 18 2023

A129305 Encodes multisets of least prime signatures in reverse-lex order: replace A036035 with A080688 then calculate all possible factorizations of the resulting values, recode each factor using A064553(n) and then multiply the terms.

Original entry on oeis.org

1, 2, 4, 5, 6, 11, 8, 10, 17, 12, 15, 22, 31, 42, 69, 77, 86, 109, 16, 20, 25, 34, 47, 24, 30, 44, 55, 51, 62, 83, 36, 45, 66, 76, 95, 121, 93, 118, 149, 84, 105, 138, 154, 172, 215, 253, 201, 217, 218, 277, 546, 834, 861, 897, 994, 1001, 1118, 1529, 1633, 1763, 1041

Offset: 0

Alford Arnold, May 02 2007

nonn

Sequence A035310 counts the values in each subtable and illustrates relationships with A000041, A000079, A000110 etc. Sequence A096443 counts the values associated with each least prime signature. (Cf. A025487 and A036035.)

			The encoded values can be arranged in tabular form based on the number of factors and the associated numeric partitions as indicated below:
2..................................................
.....4.....5........................................
.....6.....11........................................
...............8.....10.....17.........................
...............12....15.....31.........................
.....................22..............................
...............42....69.....109.........................
.....................77..............................
.....................86..............................
.................................16.....20.....25.....34.....47
.................................24.....30.....55.....51.....83
........................................44............62.....
.................................36.....45.....95.....93.....149
........................................66.....121...118.....
........................................76...............
.................................84.....105.....215.....201.....277
........................................138.....253.....217.....
........................................154.............218.....
........................................172...............
................................546.....834.....1529.....1041.....1289
........................................861.....1633.....1138.....
........................................897.....1763.....1253.....
........................................994..............1417.....
........................................1001...............
........................................1118...............

Cf. A025487, A035310, A036035, A064553, A080688, A096443.

A130274 Table of Encoded Bell Multisets using A064553 (cf. A129305).

Original entry on oeis.org

2, 6, 11, 42, 69, 77, 86, 109, 546, 834, 861, 897, 994, 1001, 1118, 1529, 1633, 1763, 1041, 1138, 1253, 1417, 1289, 15834, 16086, 19578, 19929, 23842, 24186, 24969, 26013, 28826, 29029, 32422, 26427, 29491, 30441, 30873, 32938, 35642, 35893

Offset: 1

Alford Arnold, May 25 2007

nonn

The sort sequence for A130274 is as described in A129305.

			Consider the five primes {2, 3, 5, 7, 11} then create the subsets {2,7} and {3,5,11} which corresponds to the Murasaki diagram showing the first and fourth objects connected and the second,third and fifth connected.
Calculate A000040(2*7-1) times A000040(3*5*11-1) = A000040(13)*A000040(164) = 41*971 = 39811. Therefore 39811 is a member.

Cf. A000110, A064553, A129305.

A064559 Number of iterations in A064553 to reach a fixed point.

Original entry on oeis.org

0, 0, 0, 0, 1, 0, 2, 0, 0, 1, 1, 0, 3, 2, 1, 0, 1, 0, 1, 1, 2, 1, 2, 0, 1, 3, 0, 2, 2, 1, 1, 0, 1, 1, 2, 0, 4, 1, 3, 1, 3, 2, 2, 1, 1, 2, 1, 0, 2, 1, 1, 3, 2, 0, 1, 2, 1, 2, 1, 1, 2, 1, 2, 0, 3, 1, 2, 1, 2, 2, 3, 0, 2, 4, 1, 1, 2, 3, 3, 1, 0, 3, 1, 2, 1, 2, 2, 1, 2, 1, 3, 2, 1, 1, 1, 0, 4, 2, 1, 1, 1, 1, 3, 3, 2

Offset: 1

Reinhard Zumkeller, Sep 21 2001

nonn

This is well-defined since A064553(n) <= n.

			a(12) = 0 as A064553(12) = 12.
a(26) = 3 as A064553(26) = 14, A064553(14) = 10, A064553(10) = 8 and A064553(8) = 8.

Antti Karttunen, Table of n, a(n) for n = 1..10000

Cf. A064553.

b[n_] := b[n] = If[n == 1, 1, Times @@ (PrimePi[#[[1]]]^#[[2]]& /@ FactorInteger[n])];
c[n_] := c[n] = If[n == 1, 1, If[PrimeQ[n], Prime[PrimePi[n] + 1], Times @@ (c[#1]^#2& @@@ FactorInteger[n])]];
A064553[n_] := b[c[n]];
a[n_] := Length[FixedPointList[A064553, n]] - 2;
Array[a, 105] (* Jean-François Alcover, Dec 02 2021 *)

(define (A064559 n) (let ((k (A064553 n))) (if (= k n) 0 (+ 1 (A064559 k))))) ;; Antti Karttunen, Jul 23 2017

a(A003586(n)) = 0.

A001055 The multiplicative partition function: number of ways of factoring n with all factors greater than 1 (a(1) = 1 by convention).

Original entry on oeis.org

1, 1, 1, 2, 1, 2, 1, 3, 2, 2, 1, 4, 1, 2, 2, 5, 1, 4, 1, 4, 2, 2, 1, 7, 2, 2, 3, 4, 1, 5, 1, 7, 2, 2, 2, 9, 1, 2, 2, 7, 1, 5, 1, 4, 4, 2, 1, 12, 2, 4, 2, 4, 1, 7, 2, 7, 2, 2, 1, 11, 1, 2, 4, 11, 2, 5, 1, 4, 2, 5, 1, 16, 1, 2, 4, 4, 2, 5, 1, 12, 5, 2, 1, 11, 2, 2, 2, 7, 1, 11, 2, 4, 2, 2, 2, 19, 1, 4, 4, 9, 1, 5, 1

Offset: 1

N. J. A. Sloane

From David W. Wilson, Feb 28 2009: (Start)
By a factorization of n we mean a multiset of integers > 1 whose product is n.
For example, 6 is the product of 2 such multisets, {2, 3} and {6}, so a(6) = 2.
Similarly 8 is the product of 3 such multisets, {2, 2, 2}, {2, 4} and {8}, so a(8) = 3.
1 is the product of 1 such multiset, namely the empty multiset {}, whose product is by definition the multiplicative identity 1. Hence a(1) = 1. (End)
a(n) = # { k | A064553(k) = n }. - Reinhard Zumkeller, Sep 21 2001; Benoit Cloitre and N. J. A. Sloane, May 15 2002
Number of members of A025487 with n divisors. - Matthew Vandermast, Jul 12 2004
See sequence A162247 for a list of the factorizations of n and a program for generating the factorizations for any n. - T. D. Noe, Jun 28 2009
So a(n) gives the number of different prime signatures that can be found among the integers that have n divisors. - Michel Marcus, Nov 11 2015
For n > 0, also the number of integer partitions of n with product n, ranked by A301987. For example, the a(12) = 4 partitions are: (12), (6,2,1,1,1,1), (4,3,1,1,1,1,1), (3,2,2,1,1,1,1,1). See also A380218. In general, A379666(m,n) = a(n) for any m >= n. - Gus Wiseman, Feb 07 2025

			1: 1, a(1) = 1
2: 2, a(2) = 1
3: 3, a(3) = 1
4: 4 = 2*2, a(4) = 2
6: 6 = 2*3, a(6) = 2
8: 8 = 2*4 = 2*2*2, a(8) = 3
etc.

M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 844.
S. R. Finch, Mathematical Constants, Cambridge, 2003, pp. 292-295.
Amarnath Murthy and Charles Ashbacher, Generalized Partitions and Some New Ideas on Number Theory and Smarandache Sequences, Hexis, Phoenix; USA 2005. See Section 1.4.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
G. Tenenbaum, Introduction to analytic and probabilistic number theory, Cambridge University Press, 1995, p. 198, exercise 9 (in the third edition 2015, p. 296, exercise 211).

T. D. Noe, Table of n, a(n) for n = 1..10000
M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy].
D. Beckwith, Problem 10669, Amer. Math. Monthly 105 (1998), p. 559.
R. E. Canfield, P. Erdős and C. Pomerance, On a Problem of Oppenheim concerning "Factorisatio Numerorum", J. Number Theory 17 (1983), 1-28.
R. E. Canfield, P. Erdős and C. Pomerance, On a Problem of Oppenheim concerning "Factorisatio Numerorum", J. Number Theory 17 (1983), 1-28. [A second link to the same paper.]
Marc Chamberland, Colin Johnson, Alice Nadeau, and Bingxi Wu, Multiplicative Partitions, Electronic Journal of Combinatorics, 20(2) (2013), #P57.
S. R. Finch, Kalmar's composition constant, Jun 05 2003. [Cached copy, with permission of the author]
Shamik Ghosh, Counting number of factorizations of a natural number, arXiv:0811.3479 [cs.DM], 2008.
R. K. Guy and R. J. Nowakowski, Monthly unsolved problems, 1969-1995, Amer. Math. Monthly, 102 (1995), 921-926.
John F. Hughes and J. O. Shallit, On the Number of Multiplicative Partitions, American Mathematical Monthly 90(7) (1983), 468-471.
Cao Hui-Zhong and Ku Tung-Hsin, On the Enumeration Function of Multiplicative Partitions, Math. Balkanica, Vol. 4 (1990), Fasc. 3-4.
Florian Luca, Anirban Mukhopadhyay and Kotyada Srinivas, On the Oppenheim's "factorisatio numerorum" function, arXiv:0807.0986 [math.NT], 2008.
Pankaj Jyoti Mahanta, On the number of partitions of n whose product of the summands is at most n, arXiv:2010.07353 [math.CO], 2020.
Amarnath Murthy, Generalization of Partition Function (Introducing the Smarandache Factor Partition) [Broken link]
Amarnath Murthy and Charles Ashbacher, Generalized Partitions and Some New Ideas on Number Theory and Smarandache Sequences, Hexis, Phoenix; USA 2005. See Section 1.4.
Paul Pollack, On the parity of the number of multiplicative partitions and related problems, Proc. Amer. Math. Soc. 140 (2012), 3793-3803.
Marko Riedel, Calculating the multiplicative partition function in Maple with the Polya Enumeration Theorem
Eric Weisstein's World of Mathematics, Unordered Factorization
Wikipedia, Multiplicative Partition Function
Index entries for "core" sequences

A045782 gives the range of a(n).
For records see A033833, A033834.
Cf. A002033, A045778 (strict version), A050322, A050336, A064553, A064554, A064555, A077565, A051731, A005171, A097296, A190938, A216599, A216600, A216601, A216602.
Row sums of A316439 (for n>1).
Cf. A096276 (partial sums).
The additive version is A000041 (integer partitions), strict A000009.
Row sums of A318950.
A002865 counts partitions into parts > 1.
A069016 counts distinct sums of factorizations.
A319000 counts partitions by product and sum, row sums A319916.
A379666 (transpose A380959) counts partitions by sum and product, without 1's A379668, strict A379671.
Cf. A003963, A057567, A057568 (strict A379733), A114324, A301987, A319005, A379734.

a001055 = (map last a066032_tabl !!) . (subtract 1)
-- Reinhard Zumkeller, Oct 01 2012

public class MultiPart {
    public static void main(String[] argV) {
        for (int i=1;i<=100;++i) System.out.println(1+getDivisors(2,i));
    }
    public static int getDivisors(int min,int n) {
        int total = 0;
        for (int i=min;i=i) { ++total; if (n/i>i) total+=getDivisors(i,n/i); }
        return total;
    }
} \\ Scott R. Shannon, Aug 21 2019

with(numtheory):
T := proc(n::integer, m::integer)
        local A, summe, d:
        if isprime(n) then
                if n <= m then
                        return 1;
                end if:
                return 0 ;
        end if:
        A := divisors(n) minus {n, 1}:
        for d in A do
                if d > m then
                        A := A minus {d}:
                end if:
        end do:
        summe := add(T(n/d,d),d=A) ;
        if n <=m then
                summe := summe + 1:
        end if:
        summe ;
end proc:
A001055 := n -> T(n, n):
[seq(A001055(n), n=1..100)]; # Reinhard Zumkeller and Ulrich Schimke (ulrschimke(AT)aol.com)

c[1, r_] := c[1, r]=1; c[n_, r_] := c[n, r] = Module[{ds, i}, ds = Select[Divisors[n], 1 < # <= r &]; Sum[c[n/ds[[i]], ds[[i]]], {i, 1, Length[ds]}]]; a[n_] := c[n, n]; a/@Range[100] (* c[n, r] is the number of factorizations of n with factors <= r. - Dean Hickerson, Oct 28 2002 *)
T[, 1] = T[1, ] = 1;
T[n_, m_] := T[n, m] = DivisorSum[n, Boole[1 < # <= m] * T[n/#, #]&];
a[n_] := T[n, n];
a /@ Range[100] (* Jean-François Alcover, Jan 03 2020 *)

/* factorizations of n with factors <= m (n,m positive integers) */
fcnt(n,m) = {local(s);s=0;if(n == 1,s=1,fordiv(n,d,if(d > 1 & d <= m,s=s+fcnt(n/d,d))));s}
A001055(n) = fcnt(n,n) \\ Michael B. Porter, Oct 29 2009

\\ code using Dirichlet g.f., based on Somos's code for A007896
{a(n) = my(A, v, w, m);
if(
n<1, 0,
\\ define unit vector v = [1, 0, 0, ...] of length n
v = vector(n, k, k==1);
for(k=2, n,
m = #digits(n, k) - 1;
\\ expand 1/(1-x)^k out far enough
A = (1 - x)^ -1 + x * O(x^m);
\\ w = zero vector of length n
w = vector(n);
\\ convert A to a vector
for(i=0, m, w[k^i] = polcoeff(A, i));
\\ build the answer
v = dirmul(v, w)
);
v[n]
)
};
\\ produce the sequence
vector(100,n,a(n)) \\ N. J. A. Sloane, May 26 2014

v=vector(100, k, k==1); for(n=2, #v, v+=dirmul(v, vector(#v, k, (k>1) && n^valuation(k,n)==k)) ); v \\ Max Alekseyev, Jul 16 2014

from sympy import divisors, isprime
def T(n, m):
    if isprime(n): return 1 if n<=m else 0
    A=filter(lambda d: d<=m, divisors(n)[1:-1])
    s=sum(T(n//d, d) for d in A)
    return s + 1 if n<=m else s
def a(n): return T(n, n)
print([a(n) for n in range(1, 106)]) # Indranil Ghosh, Aug 19 2017

The asymptotic behavior of this sequence was studied by Canfield, Erdős & Pomerance and Luca, Mukhopadhyay, & Srinivas. - Jonathan Vos Post, Jul 07 2008
Dirichlet g.f.: Product_{k>=2} 1/(1 - 1/k^s).
If n = p^k for a prime p, a(n) = partitions(k) = A000041(k).
Since the sequence a(n) is the right diagonal of A066032, the given recursive formula for A066032 applies (see Maple program). - Reinhard Zumkeller and Ulrich Schimke (ulrschimke(AT)aol.com)
a(A002110(n)) = A000110(n).
a(p^k*q^k) = A002774(k) if p and q are distinct primes. - R. J. Mathar, Jun 06 2024
a(n) = A028422(n) + 1. - Gus Wiseman, Feb 07 2025

Incorrect assertion about asymptotic behavior deleted by N. J. A. Sloane, Jun 08 2009

cp's OEIS Frontend

A080688 Resort the index of A064553 using A080444 and maintaining ascending order within each grouping: seen as a triangle read by rows, the n-th row contains the A001055(n) numbers m with A064553(m)=n.

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Haskell

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A064554 a(n) = Min {k | A064553(k) = n}.

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A064555 a(n) = max { k | A064553(k) = n }.

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A064557 a(n) = # { p | A064553(k) = p prime and k <= n}.

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A064558 a(n) = A064553(A064553(n)).

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A064600 a(n) indicates the position of 5 after n iterations of A064553.

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A129305 Encodes multisets of least prime signatures in reverse-lex order: replace A036035 with A080688 then calculate all possible factorizations of the resulting values, recode each factor using A064553(n) and then multiply the terms.

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A130274 Table of Encoded Bell Multisets using A064553 (cf. A129305).

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A064559 Number of iterations in A064553 to reach a fixed point.

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