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 1-10 of 12 results. Next

A093677 Self-convolution of A093659, which is the first column of triangle A093658.

Original entry on oeis.org

1, 2, 3, 6, 7, 10, 14, 24, 27, 30, 42, 44, 58, 68, 104, 120, 147, 150, 230, 164, 254, 256, 436, 240, 346, 356, 604, 408, 680, 696, 1272, 720, 987, 990, 1694, 1004, 1786, 1720, 3316, 1080, 1886, 1888, 3696, 1872, 3772, 3576, 7608, 1560, 2530, 2540, 4828, 2592
Offset: 1

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Author

Paul D. Hanna, Apr 09 2004

Keywords

Comments

A093659 consists only of factorial numbers, where A093659(2^n) = n!.

Crossrefs

Formula

a(2^n) = (n+1)!

A093658 Lower triangular matrix, read by rows, defined as the convergent of the concatenation of matrices using the iteration: M(n+1) = [[M(n),0*M(n)],[M(n)^2,M(n)]], with M(0) = [1].

Original entry on oeis.org

1, 1, 1, 1, 0, 1, 2, 1, 1, 1, 1, 0, 0, 0, 1, 2, 1, 0, 0, 1, 1, 2, 0, 1, 0, 1, 0, 1, 6, 2, 2, 1, 2, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 2, 1, 0, 0, 0, 0, 0, 0, 1, 1, 2, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 6, 2, 2, 1, 0, 0, 0, 0, 2, 1, 1, 1, 2, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 6, 2, 0, 0, 2, 1, 0, 0, 2, 1, 0, 0, 1, 1
Offset: 1

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Author

Paul D. Hanna, Apr 08 2004

Keywords

Comments

Related to factorials, the incomplete gamma function (A010842) and the total number of arrangements of sets (A000522).
First column forms A093659, where A093659(2^n) = n! for n>=0.
Row sums form A093660, where A093660(2^n) = A000522(n) for n>=0.
Partial sums of the row sums form A093661, where A093661(2^n) = A010842(n) for n>=0.

Examples

			Let M(n) be the lower triangular matrix formed from the first 2^n rows.
To generate M(3) from M(2), take the matrix square of M(2):
[1,0,0,0]^2=[1,0,0,0]
[1,1,0,0]...[2,1,0,0]
[1,0,1,0]...[2,0,1,0]
[2,1,1,1]...[6,2,2,1]
and append M(2)^2 to the bottom left corner and M(2) to the bottom right:
[1],
[1,1],
[1,0,1],
[2,1,1,1],
.........
[1,0,0,0],[1],
[2,1,0,0],[1,1],
[2,0,1,0],[1,0,1],
[6,2,2,1],[2,1,1,1].
Repeating this process converges to triangle A093658.
		

Crossrefs

Formula

T(2^n, 1) = n! for n>=0.

A269221 Factorial of the sum of decimal digits of n.

Original entry on oeis.org

1, 1, 2, 6, 24, 120, 720, 5040, 40320, 362880, 1, 2, 6, 24, 120, 720, 5040, 40320, 362880, 3628800, 2, 6, 24, 120, 720, 5040, 40320, 362880, 3628800, 39916800, 6, 24, 120, 720, 5040, 40320, 362880, 3628800, 39916800, 479001600, 24, 120, 720, 5040
Offset: 0

Views

Author

M. F. Hasler, Mar 15 2016

Keywords

Comments

Sequence A093659 is the binary (base 2) version.

Crossrefs

Programs

  • Mathematica
    Table[Total[IntegerDigits[n]]!,{n,0,50}] (* Harvey P. Dale, Dec 19 2021 *)
  • PARI
    A269221(n)=sumdigits(n)!

Formula

a(n) = A000142(A007953(n)).

A139329 a(n) = (factorial of the number of 0's in the binary expansion of n).

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 1, 6, 2, 2, 1, 2, 1, 1, 1, 24, 6, 6, 2, 6, 2, 2, 1, 6, 2, 2, 1, 2, 1, 1, 1, 120, 24, 24, 6, 24, 6, 6, 2, 24, 6, 6, 2, 6, 2, 2, 1, 24, 6, 6, 2, 6, 2, 2, 1, 6, 2, 2, 1, 2, 1, 1, 1, 720, 120, 120, 24, 120, 24, 24, 6, 120, 24, 24, 6, 24, 6, 6, 2, 120, 24, 24, 6, 24, 6, 6, 2, 24, 6, 6, 2, 6, 2, 2, 1, 120
Offset: 0

Views

Author

Max Sills, Apr 13 2008

Keywords

Comments

Number of permutation symmetries of the 0's in the binary expansion of n. Consider the symmetric group that permutes floor(log_2(n)) elements acting on the 0's.

Crossrefs

Cf. A000142, A023416, A080791, A093659 (factorial of the number of 1's in binary expansion of n).

Programs

  • Mathematica
    a[n_] := DigitCount[n, 2, 0]!; Array[a, 100, 0] (* Amiram Eldar, Jul 29 2023 *)
  • PARI
    a(n) = (#binary(n)-hammingweight(n))!; \\ Michel Marcus, Oct 24 2017

Formula

a(n) = A000142(A023416(n)) = A000142(A080791(n)). - Antti Karttunen, Oct 24 2017

Extensions

Locations of the name and the formula changed, more terms from Antti Karttunen, Oct 24 2017

A269223 Factorial of the sum of digits of n in base 3.

Original entry on oeis.org

1, 1, 2, 1, 2, 6, 2, 6, 24, 1, 2, 6, 2, 6, 24, 6, 24, 120, 2, 6, 24, 6, 24, 120, 24, 120, 720, 1, 2, 6, 2, 6, 24, 6, 24, 120, 2, 6, 24, 6, 24, 120, 24, 120, 720, 6, 24, 120, 24, 120, 720, 120, 720, 5040, 2, 6, 24, 6, 24, 120, 24, 120, 720, 6, 24, 120, 24, 120, 720, 120, 720
Offset: 0

Views

Author

M. F. Hasler, Mar 15 2016

Keywords

Comments

Sequence A093659 is the binary (base 2) and sequence A269221 is the decimal (base 10) version.

Crossrefs

Programs

  • Mathematica
    Table[Total[IntegerDigits[n, 3]]!, {n, 0, 70}] (* Michael De Vlieger, Mar 15 2016 *)
  • PARI
    A269223(n)=sumdigits(n,3)! \\ sumdigits(.,3) requires version > 2.7.1; see A053735 for a substitute.
    
  • PARI
    a(n) = vecsum(digits(n,3))!; \\ Michel Marcus, Mar 15 2016

Formula

a(n) = A000142(A053735(n)).

A136494 Number of permutation symmetries in the binary expansion of n.

Original entry on oeis.org

1, 1, 1, 2, 2, 2, 2, 6, 6, 4, 4, 6, 4, 6, 6, 24, 24, 12, 12, 12, 12, 12, 12, 24, 12, 12, 12, 24, 12, 24, 24, 120, 120, 48, 48, 36, 48, 36, 36, 48, 48, 36, 36, 48, 36, 48, 48, 120, 48, 36, 36, 48, 36, 48, 48, 120, 36, 48, 48, 120, 48, 120, 120, 720, 720
Offset: 0

Views

Author

Max Sills, Apr 13 2008

Keywords

Examples

			a(14) = 6 because there are 3! permutation symmetries of 1's * the 0! permutation symmetries of 0's.
		

Crossrefs

Programs

  • Mathematica
    a[n_] := Times @@ (DigitCount[n, 2]!); Array[a, 65, 0] (* Amiram Eldar, Jul 29 2023 *)
  • PARI
    a(n) = {if(n==0, 1, my(w=hammingweight(n)); w!*(1+logint(n,2)-w)!)} \\ Andrew Howroyd, Jan 12 2020

Formula

a(n) = A093659(n) * A139329(n).
a(n) = A000120(n)! * A080791(n)!.

Extensions

Terms a(32) and beyond from Andrew Howroyd, Jan 12 2020

A188064 Partial sums of wt(n)! where wt(n) is the Hamming weight of n (A000120).

Original entry on oeis.org

1, 2, 3, 5, 6, 8, 10, 16, 17, 19, 21, 27, 29, 35, 41, 65, 66, 68, 70, 76, 78, 84, 90, 114, 116, 122, 128, 152, 158, 182, 206, 326, 327, 329, 331, 337, 339, 345, 351, 375, 377, 383, 389, 413, 419, 443, 467, 587, 589, 595, 601, 625, 631, 655, 679, 799, 805, 829, 853, 973, 997, 1117
Offset: 0

Views

Author

Joerg Arndt, Mar 20 2011

Keywords

Comments

Partial sums of A093659, partial sums of the factorials of A000120.
A000522 is a subsequence: A000522(n)=a(2^n-1).

Crossrefs

Programs

  • Mathematica
    FoldList[Plus, 0!, Table[(Plus @@ IntegerDigits[n, 2])!, {n, 1, 70}]] (* From Olivier Gérard, Mar 23 2011 *)
    Accumulate[DigitCount[Range[0,70],2,1]!] (* Harvey P. Dale, Jun 26 2013 *)
  • PARI
    bitcount(x)=
    { /* Return Hamming weight of x */
        local(p);  p = 0;
        while ( x, p+=bitand(x, 1); x>>=1; );
        return( p );
    }
    N=65; /* that many terms */
    f=vector(N,n,bitcount(n-1)!); /* factorials of Hamming weights */
    s=vector(N); s[1]=f[1]; /* for cumulative sums */
    for (n=2,N,s[n]=s[n-1]+f[n]); /* sum up */
    s /* show terms */ /* Joerg Arndt, Mar 20 2011 */

Formula

a(n)=sum(k=0,n,wt(k)!) where wt(k) is the Hamming weight of k.

A269224 Factorial of the sum of digits of n in base 4.

Original entry on oeis.org

1, 1, 2, 6, 1, 2, 6, 24, 2, 6, 24, 120, 6, 24, 120, 720, 1, 2, 6, 24, 2, 6, 24, 120, 6, 24, 120, 720, 24, 120, 720, 5040, 2, 6, 24, 120, 6, 24, 120, 720, 24, 120, 720, 5040, 120, 720, 5040, 40320, 6, 24, 120, 720, 24, 120, 720, 5040, 120, 720, 5040, 40320, 720, 5040, 40320
Offset: 0

Views

Author

M. F. Hasler, Mar 15 2016

Keywords

Comments

See sequences A093659, A269223 and A269221 for the base 2, base 3 and base 10 analog.

Crossrefs

Programs

  • Mathematica
    Table[Total[IntegerDigits[n, 4]]!, {n, 0, 62}] (* Michael De Vlieger, Mar 15 2016 *)
  • PARI
    A269224(n)=sumdigits(n,4)! \\ sumdigits(.,4) requires version >= 2.7; see A053737 for a substitute.
    
  • PARI
    a(n) = vecsum(digits(n,4))!; \\ Michel Marcus, Mar 15 2016

Formula

a(n) = A000142(A053737(n)).

A357534 Number of compositions (ordered partitions) of n into two or more powers of 2.

Original entry on oeis.org

0, 0, 1, 3, 5, 10, 18, 31, 55, 98, 174, 306, 542, 956, 1690, 2983, 5271, 9310, 16448, 29050, 51318, 90644, 160118, 282826, 499590, 882468, 1558798, 2753448, 4863696, 8591212, 15175514, 26805983, 47350055, 83639030, 147739848, 260967362, 460972286, 814260544, 1438308328
Offset: 0

Views

Author

Ilya Gutkovskiy, Oct 02 2022

Keywords

Crossrefs

Programs

  • Maple
    b:= proc(n) option remember;
          `if`(n=0, 1, add(b(n-2^i), i=0..ilog2(n)))
        end:
    a:= n-> b(n)-`if`(2^ilog2(n)=n, 1, 0):
    seq(a(n), n=0..50);  # Alois P. Heinz, Oct 02 2022
  • Mathematica
    b[n_] := b[n] = If[n == 0, 1, Sum[b[n - 2^i], {i, 0, Floor@ Log2[n]}]];
    a[n_] :=  b[n] - If[2^Floor@Log2[n] == n, 1, 0];
    Table[a[n], {n, 0, 50}] (* Jean-François Alcover, Dec 26 2022, after Alois P. Heinz *)

Formula

a(n) = A023359(n) - A209229(n) for n > 0.

A384955 a(n) is the multinomial coefficient of the digits of n.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1, 3, 6, 10, 15, 21, 28, 36, 45, 55, 1, 4, 10, 20, 35, 56, 84, 120, 165, 220, 1, 5, 15, 35, 70, 126, 210, 330, 495, 715, 1, 6, 21, 56, 126, 252, 462, 792, 1287, 2002, 1, 7, 28, 84, 210, 462, 924, 1716, 3003, 5005
Offset: 0

Views

Author

Stefano Spezia, Jun 13 2025

Keywords

Examples

			a(35) = (3+5)!/(3!*5!) = 40320/(6*120) = 56;
a(1512) = (1+5+1+2)!/(1!*5!*1!*2!) = 362880/(120*2) = 1512.
		

Crossrefs

Programs

  • Maple
    a:= n-> (l-> combinat[multinomial](add(i,i=l), l[]))(convert(n, base, 10)):
    seq(a(n), n=0..69);  # Alois P. Heinz, Jun 15 2025
  • Mathematica
    a[n_]:=Multinomial @@IntegerDigits[n]; Array[a,70,0]
  • Python
    from math import factorial, prod
    def a(n): return factorial(sum(digits:=list(map(int, str(n))))) // prod(factorial(x) for x in digits)
    print([a(n) for n in range(70)]) # David Radcliffe, Jun 15 2025

Formula

a(n) = A269221(n)/A066459(n).
a(n) = 1 iff n is equal to 0 or has only one nonzero digit (cf. A037124).
Conjecture: a(n) = n iff n = 1 or n = 1512.
Showing 1-10 of 12 results. Next