A158989 Numbers n such that product of double factorials of the digits of n equals sigma(n).

1, 54, 62, 4190, 4920, 10538, 12376, 16065, 16732, 26345, 37236, 47026, 48323, 53480, 56712, 58520, 61209, 62337, 65163, 83720, 84135, 94520, 100980, 126238, 135266, 141078, 143726, 146910, 147354, 154238, 174217, 183505, 185334, 207328

Offset

1,2

Links

Table of n, a(n) for n=1..34.

Example

sigma(444119)=4!!*4!!*4!!*1!!*1!!*9!!, so 444119 is in the sequence.

Mathematica

Select[Range[210000], DivisorSigma[1, # ]==Apply[Times, IntegerDigits[ # ]!! ]&]

Crossrefs

Cf. A137603, A158990, A158991, A158992.

Sequence in context: A095511 A095501 A318235 * A088489 A025331 A025323

Adjacent sequences: A158986 A158987 A158988 * A158990 A158991 A158992

Keyword

base,easy,nonn

Author

Farideh Firoozbakht, Jul 07 2009

Status

approved