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 1-3 of 3 results.

A188264 Numbers m that are divisible by the product of the factorials of their digits in base 10.

Original entry on oeis.org

1, 2, 10, 11, 12, 20, 30, 100, 101, 102, 110, 111, 112, 120, 132, 200, 210, 212, 220, 240, 300, 312, 1000, 1001, 1002, 1010, 1011, 1012, 1020, 1032, 1100, 1101, 1102, 1104, 1110, 1111, 1112, 1120, 1200, 1210, 1212, 1220, 1320, 2000, 2010, 2012, 2020, 2100, 2110, 2112
Offset: 1

Views

Author

Jaroslav Krizek, Mar 25 2011

Keywords

Examples

			Number 30 is in sequence because 30 is divisible by the product of factorials 3!*0! = 6.
		

Crossrefs

Programs

  • Haskell
    import Data.List (elemIndices)
    a188264 n = a188264_list !! (n-1)
    a188264_list =
       map (+ 1) $ elemIndices 0 $ zipWith mod [1..] $ map a066459 [1..]
    -- Reinhard Zumkeller, Oct 11 2011
  • Mathematica
    Select[Range[2200],Divisible[#,Times@@(IntegerDigits[#]!)]&] (* Harvey P. Dale, May 24 2017 *)

A247227 Numbers that divide the sum of the factorials of their digits in base 10.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 19, 56, 71, 93, 145, 219, 758, 768, 7584, 7684, 9696, 10081, 21993, 40585
Offset: 1

Views

Author

Jaroslav Krizek, Dec 25 2014

Keywords

Comments

Numbers n such that n divides A061602(n).
Finite sequence with 23 terms.
Subsequence of numbers n such that A061602(n) >= n. The largest such number is 1999999.
Sequence of values A061602(a(n)) / a(n): 1, 1, 2, 6, 24, 120, 720, 5040, 40320, 19099, 15, 71, 3902, 1, 1657, 60, 60, 6, 6, 75, 4, 33, 1.
Supersequence of A014080 (whose terms are the numbers n such that A061602(n) / n = 1).

Examples

			19 is in the sequence because 19 divides 1! + 9! = 1 + 362880 = 362881; 362881 / 19 = 19099.
		

Crossrefs

Programs

  • Magma
    [n: n in [1..2000000] | &+[ Factorial(d): d in Intseq(n)] mod n eq 0]
    
  • Mathematica
    Select[Range[50000], Mod[Plus @@ Factorial[IntegerDigits[#]], #] == 0 &] (* Michael De Vlieger, Dec 26 2014 *)
  • PARI
    for(k=1,10^5,d=digits(k);s=sum(i=1,#d,d[i]!);if(!(s%k),print1(k,", "))) \\ Derek Orr, Dec 30 2014

A261556 Numbers that divide the sum of the product of the factorials of their digits and the sum of the factorials of their digits.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 13, 17, 54, 86, 573, 768, 999, 6143, 94584, 159287, 27167549, 40548073, 72382636, 131092614, 340720926, 1161216721, 2955383683, 3892089702, 5304046976, 6554754648, 72338498624, 279445396448, 331043595868, 466026097373, 962499474063, 3082891291712
Offset: 1

Views

Author

Paolo Omodei-Zorini, Aug 24 2015

Keywords

Examples

			54 is in the list because 5! = 120, 4! = 24,  120*24=2880, 120+24=144, 2880+144=3024, 3024/54=56.
		

Crossrefs

Programs

  • Mathematica
    fQ[n_] := Block[{d = IntegerDigits[n]!}, Mod[Times @@ d + Total@ d, n] == 0]; Select[Range@ 1000000, fQ] (* Michael De Vlieger, Aug 26 2015 *)
  • PARI
    isok(n) = my(d = digits(n)); ((sum(k=1,#d, d[k]!)+prod(k=1,#d, d[k]!)) % n) == 0; \\ Michel Marcus, Aug 25 2015

Extensions

a(24)-a(25) from Jon E. Schoenfield, Aug 24 2015
a(26)-a(30) from Giovanni Resta, Aug 26 2015
a(31)-a(34) from Chai Wah Wu, May 04 2019
a(35) from Giovanni Resta, Aug 19 2019
Showing 1-3 of 3 results.