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A093685 In binary representation: numbers not occurring in their factorial. 5
0, 5, 11, 13, 15, 17, 31, 37, 55, 81, 164, 395, 513, 517, 619, 1041, 1287, 1538, 2108, 2116, 2137, 2138, 2282, 2352, 2363, 2432, 2466, 2524, 4278, 4511, 4758, 4766, 4852, 4854, 5136, 5586, 8396, 8463, 8883, 9707, 10351, 16528, 17279, 19469, 21244, 24472 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

A093684(a(n)) = 0, complement of A093686.

LINKS

Table of n, a(n) for n=1..46.

EXAMPLE

5! = 1*2*3*4*5 = 120 -> '1111000', in which '101'=5 is not contained, so 5 is in the sequence.

MATHEMATICA

f[n_] := ToString[ FromDigits[ IntegerDigits[n, 2]]]; Select[ Range[ 29000], StringPosition[ f[ #! ], f[ # ]] == {} &] (* Robert G. Wilson v, Apr 15 2004 *)

PROG

(Python)

def aupto(limit):

  kfact, alst = 1, [0]

  for k in range(1, limit+1):

    kb, kfact = bin(k)[2:], kfact * k

    kfactb = bin(kfact)[2:]

    if kb not in kfactb: alst.append(k)

  return alst

print(aupto(25000)) # Michael S. Branicky, May 01 2021

CROSSREFS

Cf. A036603, A007088, A000142, A093826.

Sequence in context: A287123 A227146 A251965 * A337658 A206548 A206547

Adjacent sequences:  A093682 A093683 A093684 * A093686 A093687 A093688

KEYWORD

nonn,base

AUTHOR

Reinhard Zumkeller, Apr 10 2004

EXTENSIONS

More terms from Robert G. Wilson v, Apr 15 2004

STATUS

approved

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Last modified August 5 13:10 EDT 2021. Contains 346469 sequences. (Running on oeis4.)