

A202242


n such that the sum of digit !! of n equals the sum of dn, 1<d<n.


0




OFFSET

1,1


COMMENTS

No further terms less than 10^8.
The double factorial n!! (A006882) of a positive integer n is the product of the positive integers <= n that have the same parity as n.


LINKS



EXAMPLE

56 is in the sequence because 5!! + 6!! = 15 + 48 = 63, and sum of the divisors 1< d< 56 = sigma(56)  56  1 = 120  56  1 = 63.


MATHEMATICA

Q[n_]:=Module[{a=Total[Rest[Most[Divisors[n]]]]}, a == Total[IntegerDigits[n]!!]]; Select[Range[2, 10^5], Q]


CROSSREFS



KEYWORD

nonn,hard,base


AUTHOR



STATUS

approved



