A174569 Numbers n such that sum of factorials of digits of n is a power of 2.

1, 2, 10, 11, 22, 23, 32, 102, 103, 112, 113, 120, 121, 130, 131, 200, 201, 210, 211, 234, 235, 243, 253, 300, 301, 310, 311, 324, 325, 342, 352, 423, 432, 523, 532, 1000, 1001, 1010, 1011, 1034, 1035, 1043, 1053, 1100, 1101, 1110, 1111, 1134, 1135, 1143, 1153, 1304, 1305, 1314, 1315, 1340

Offset

1,2

Links

Table of n, a(n) for n=1..56.

Example

234 is in the sequence because 2! + 3! + 4! = 32 = 2^5.

Maple

with(numtheory):for n from 1 to 2000 do:l:=length(n):n0:=n:s:=0:for m from
  1 to l do:q:=n0:u:=irem(q, 10):v:=iquo(q, 10):n0:=v :s:=s+u!:od: q:= evalf(log[2](s));
  if floor(q)= q then printf(`%d, `, n):else fi:od:

Mathematica

With[{pwrs2 = 2^Range[0, 200]}, Select[Range[1500], MemberQ[pwrs2, Total[IntegerDigits[#]!]] &]] (* Harvey P. Dale, Jan 03 2011 *)

Prog

(Sage) A174569 = list(n for n in IntegerRange(1, 2000) if sum(factorial(d) for d in n.digits()).is_power_of(2))

Crossrefs

Sequence in context: A131096 A069263 A356520 * A179884 A174570 A072545

Adjacent sequences: A174566 A174567 A174568 * A174570 A174571 A174572

Keyword

nonn,base

Author

Michel Lagneau, Nov 29 2010

Status

approved