A059589 -id:A059589 - cp's OEIS frontend

A059590 Numbers obtained by reinterpreting base-2 representation of n in the factorial base: a(n) = Sum_{k>=0} A030308(n,k)*A000142(k+1).

0, 1, 2, 3, 6, 7, 8, 9, 24, 25, 26, 27, 30, 31, 32, 33, 120, 121, 122, 123, 126, 127, 128, 129, 144, 145, 146, 147, 150, 151, 152, 153, 720, 721, 722, 723, 726, 727, 728, 729, 744, 745, 746, 747, 750, 751, 752, 753, 840, 841, 842, 843, 846, 847, 848, 849, 864, 865

Offset: 0

Henry Bottomley, Jan 24 2001

Numbers that are sums of distinct factorials (0! and 1! not treated as distinct).
Complement of A115945; A115944(a(n)) > 0; A115647 is a subsequence. - Reinhard Zumkeller, Feb 02 2006
A115944(a(n)) = 1. - Reinhard Zumkeller, Dec 04 2011
From Tilman Piesk, Jun 04 2012: (Start)
The inversion vector (compare A007623) of finite permutation a(n) (compare A055089, A195663) has only zeros and ones. Interpreted as a binary number it is 2*n (or n when the inversion vector is defined without the leading 0).
The inversion set of finite permutation a(n) interpreted as a binary number (compare A211362) is A211364(n).
(End)

			128 is in the sequence since 5! + 3! + 2! = 128.
a(22) = 128. a(22) = a(6) + (1 + floor(log(16) / log(2)))! = 8 + 5! = 128. Also, 22 = 10110_2. Therefore, a(22) = 1 * 5! + 0 * 4! + 1 * 3! + 1 + 2! + 0 * 0! = 128. - _David A. Corneth_, Aug 21 2016

Reinhard Zumkeller (terms 0..500) & Antti Karttunen, Table of n, a(n) for n = 0..8191
Index entries for sequences related to factorial base representation
Index entries for sequences related to factorial numbers

Cf. A007088, A007623, A014597, A051760, A051761, A059589.
Indices of zeros in A257684.
Cf. A275736 (left inverse).
Cf. A025494, A060112 (subsequences).
Cf. A153880, A225901.
Subsequence of A060132, A256450 and A275804.
Other sequences that are built by replacing 2^k in the binary representation with other numbers: A029931 (naturals), A089625 (primes), A022290 (Fibonacci), A197433 (Catalans), A276091 (n*n!), A275959 ((2n)!/2). Cf. also A276082 & A276083.

import Data.List (elemIndices)
a059590 n = a059590_list !! n
a059590_list = elemIndices 1 $ map a115944 [0..]
-- Reinhard Zumkeller, Dec 04 2011

[seq(bin2facbase(j),j=0..64)]; bin2facbase := proc(n) local i; add((floor(n/(2^i)) mod 2)*((i+1)!),i=0..floor_log_2(n)); end;
floor_log_2 := proc(n) local nn,i; nn := n; for i from -1 to n do if(0 = nn) then RETURN(i); fi; nn := floor(nn/2); od; end;
# next Maple program:
a:= n-> (l-> add(l[j]*j!, j=1..nops(l)))(Bits[Split](n)):
seq(a(n), n=0..57);  # Alois P. Heinz, Aug 12 2025

a[n_] :=  Reverse[id = IntegerDigits[n, 2]].Range[Length[id]]!; Table[a[n], {n, 0, 60}] (* Jean-François Alcover, Jun 19 2012, after Philippe Deléham *)

a(n) = if(n>0, a(n-msb(n)) + (1+logint(n,2))!, 0)
msb(n) = 2^#binary(n)>>1
{my(b = binary(n)); sum(i=1,#b,b[i]*(#b+1-i)!)} \\ David A. Corneth, Aug 21 2016

def facbase(k, f):
    return sum(f[i] for i, bi in enumerate(bin(k)[2:][::-1]) if bi == "1")
def auptoN(N): # terms up to N factorial-base digits; 13 generates b-file
    f = [factorial(i) for i in range(1, N+1)]
    return list(facbase(k, f) for k in range(2**N))
print(auptoN(5)) # Michael S. Branicky, Oct 15 2022

G.f. 1/(1-x) * Sum_{k>=0} (k+1)!*x^2^k/(1+x^2^k). - Ralf Stephan, Jun 24 2003
a(n) = Sum_{k>=0} A030308(n,k)*A000142(k+1). - Philippe Deléham, Oct 15 2011
From Antti Karttunen, Aug 19 2016: (Start)
a(0) = 0, a(2n) = A153880(a(n)), a(2n+1) = 1+A153880(a(n)).
a(n) = A225901(A276091(n)).
a(n) = A276075(A019565(n)).
a(A275727(n)) = A276008(n).
A275736(a(n)) = n.
A276076(a(n)) = A019565(n).
A007623(a(n)) = A007088(n).
(End)
a(n) = a(n - mbs(n)) + (1 + floor(log(n) / log(2)))!. - David A. Corneth, Aug 21 2016

Name changed (to emphasize the functional nature of the sequence) with the old definition moved to the comments by Antti Karttunen, Aug 21 2016

A025494 Squares which are the sum of factorials of distinct integers (probably finite).

Original entry on oeis.org

1, 4, 9, 25, 121, 144, 729, 841, 5041, 5184, 45369, 46225, 363609, 403225, 3674889, 1401602635449

Offset: 1

David W. Wilson

nonn

No other elements < 31!. - Paul.Jobling(AT)WhiteCross.com, Aug 10 2000

If there are any terms in either A014597 or A025494 beyond the last one given (i.e., n = 1183893 in A014597; equivalently n^2 = 1401602635449 in A025494), then n^2 must be greater than 48! (about 1.24139*10^61). - Jon E. Schoenfield, Aug 04 2006

Shyam Sunder Gupta, Fascinating Factorials, Exploring the Beauty of Fascinating Numbers, Springer (2025) Ch. 16, 411-442.

Cf. A002034, A018194, A051760, A051761, A014597, A059589.

Subsequence of A059589.

A014597 Numbers k such that k^2 is a sum of distinct factorials.

Original entry on oeis.org

1, 3, 5, 11, 12, 27, 29, 71, 72, 213, 215, 603, 635, 1917, 1183893

Offset: 1

Eric W. Weisstein

a(16)^2 > 48! (about 1.24139*10^61), if it exists. - Jon E. Schoenfield, Aug 04 2006
A197183(a(n)) = 1. - Reinhard Zumkeller, Dec 04 2011
a(16) > 4.3*10^55 if it exists. - Bert Dobbelaere, Sep 16 2020

			1183893^2 = 1! + 2! + 3! + 7! + 8! + 9! + 10! + 11! + 12! + 13! + 14! + 15!.
2 is not a member since 4 is not a sum of distinct factorials.

Posting by Dan Hoey to math-fun mailing list.

Shyam Sunder Gupta, Fascinating Factorials, Exploring the Beauty of Fascinating Numbers, Springer (2025) Ch. 16, 411-442.
Eric Weisstein's World of Mathematics, Factorial

Cf. A025494, A051761, A059589.

import Data.List (elemIndices)
a014597 n = a014597_list !! (n-1)
a014597_list = tail $ elemIndices 1 $ map a197183 [0..]
-- Reinhard Zumkeller, Dec 04 2011

ok[n_] := (k=1; ff={}; While[k! < n^2, AppendTo[ff, k!]; k++]; xx = Array[x, Length[ff]]; Reduce[And @@ (0 <= # <= 1 & /@ xx) && n^2 == xx.ff, xx, Integers] =!= False); ok[1] = True; Reap[Do[If[ok[n], Print[n]; Sow[n]], {n, 1, 2*10^6}]][[2, 1]] (* Jean-François Alcover, Jul 16 2012 *)

from math import factorial, isqrt
from itertools import chain, combinations
from sympy.ntheory.primetest import is_square
fac =[factorial(n) for n in range(1, 16)] # raise 16 to search higher
def powerset(s): # skipping empty set
  return chain.from_iterable(combinations(s, r) for r in range(1, len(s)+1))
gen = (isqrt(sum(s)) for s in powerset(fac) if is_square(sum(s)))
print(sorted(set(gen))) # Michael S. Branicky, Jan 03 2021

15th term from Jud McCranie, who remarks that there are no others involving terms < 21!.

A051761 Numbers that are simultaneously a sum of factorials of distinct integers and of the form a^b with b >= 2.

Original entry on oeis.org

0, 1, 4, 8, 9, 25, 27, 32, 121, 128, 144, 729, 841, 5041, 5184, 45369, 46225, 363609, 403225, 3674889, 1401602635449

Offset: 1

Paul.Jobling(AT)WhiteCross.com, Aug 10 2000

0! and 1! are treated as distinct.

			4 is in the sequence since 2! + 1! + 0! = 4 = 2^2.

Cf. A025494, A051760, A059589.

A290249 Numbers that are the sum of distinct primorial numbers (A002110) (not including 1).

Original entry on oeis.org

2, 6, 8, 30, 32, 36, 38, 210, 212, 216, 218, 240, 242, 246, 248, 2310, 2312, 2316, 2318, 2340, 2342, 2346, 2348, 2520, 2522, 2526, 2528, 2550, 2552, 2556, 2558, 30030, 30032, 30036, 30038, 30060, 30062, 30066, 30068, 30240, 30242, 30246, 30248, 30270, 30272, 30276, 30278, 32340, 32342, 32346, 32348, 32370

Offset: 1

Ilya Gutkovskiy, Jul 24 2017

nonn

			38 is in the sequence because 38 = 2 + 6 + 30 = 2 + 2*3 + 2*3*5.

Index entries for sequences related to primorial numbers

Cf. A002110, A059589, A059590, A143293, A177711, A276156.

Rest[f[x_] := Product[1 + x^Product[Prime[m], {m, 1, k}], {k, 1, 6}]; Exponent[#, x] & /@ List @@ Normal[Series[f[x], {x, 0, 32370}]]]

Nonzero exponents in expansion of Product_{k>=1} (1 + x^A002110(k)).

A177441 Partial sums of A014597.

Original entry on oeis.org

1, 4, 9, 20, 32, 59, 88, 159, 231, 444, 659, 1262, 1897, 3814, 1187707

Offset: 1

Jonathan Vos Post, May 08 2010

Partial sums of numbers n such that n^2 is a sum of distinct factorials. The subsequence of primes in this partial sum begins: 59, 659, 1187707. If there is a larger value (the sequence might be finite), a(n)^2 must be greater than 48! (about 1.24139 * 10^61).

			a(15) = 1 + 3 + 5 + 11 + 12 + 27 + 29 + 71 + 72 + 213 + 215 + 603 + 635 + 1917 + 1183893 is prime.

Cf. A000142, A014597, A025494, A051761, A059589.

a(n) = SUM[i=1..n] A014597(i) = SUM[i=1..n] {i such that i^2 is a sum of distinct factorials} = SUM[i=1..n] {i such that i^2 is a sum of distinct A000142(j)}.

A306583 Positive integers that cannot be represented as a sum or difference of factorials of distinct integers.

Original entry on oeis.org

11, 12, 13, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 107, 108, 109, 131, 132, 133, 155, 156, 157

Offset: 1

Ivan Stoykov, Feb 25 2019

nonn

It can be proved that any number in the gap between n! + (n-1)! + (n-2)! + ... + 2! + 1! + 0! and (n+1)! - (n! + (n-1)! + (n-2)! + ... + 2! + 1! + 0!) is in this sequence.

0! and 1! are treated as distinct. - Bernard Schott, Feb 25 2019

			10 can be represented as 10 = 0! + 1! + 2! + 3!, so it is not a term.
11 cannot be represented as a sum or a difference of factorials, so it is a term.

Cf. A000142 and A007489.

Cf. A059589 (Sums of factorials of distinct integers with 0! and 1! treated as distinct), A059590 (Sums of factorials of distinct integers with 0! and 1! treated as identical), A005165 (Alternating factorials).

Complement[Range[160], Total[# Range[0, 5]!] & /@ (IntegerDigits[ Range[3^6 - 1], 3, 6] - 1)] (* Giovanni Resta, Feb 27 2019 *)

More terms from Giovanni Resta, Feb 27 2019

cp's OEIS Frontend

A059590 Numbers obtained by reinterpreting base-2 representation of n in the factorial base: a(n) = Sum_{k>=0} A030308(n,k)*A000142(k+1).

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A025494 Squares which are the sum of factorials of distinct integers (probably finite).

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A014597 Numbers k such that k^2 is a sum of distinct factorials.

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A051761 Numbers that are simultaneously a sum of factorials of distinct integers and of the form a^b with b >= 2.

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A290249 Numbers that are the sum of distinct primorial numbers (A002110) (not including 1).

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A177441 Partial sums of A014597.

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A306583 Positive integers that cannot be represented as a sum or difference of factorials of distinct integers.

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