This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A173688 Numbers n such that the sum of square of factorial of decimal digits is prime. 0
 10, 11, 12, 13, 14, 15, 19, 20, 21, 30, 31, 40, 41, 50, 51, 90, 91, 100, 101, 110, 111, 123, 132, 133, 134, 135, 138, 143, 144, 147, 153, 156, 158, 165, 168, 169, 174, 177, 183, 185, 186, 196, 203, 213, 230, 231, 302, 303, 304, 305, 308, 312, 313, 314, 315, 318, 320 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Let the decimal expansion of n = d(0)d(1)…d(p). Numbers such that sum_{k=0..p}(d(k)!)^2   is prime. LINKS EXAMPLE a(5) =14 is in the sequence because (1!)^2 + (4!)^2 = 1 + 24^2 = 577 and 577   is prime. MAPLE with(numtheory):for n from 1 to 500 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!)^2:od: if type(s, prime)=true   then printf(`%d, `, n):else fi:od: MATHEMATICA Select[Range[400], PrimeQ[Total[(IntegerDigits[#]!)^2]]&]  (* From Harvey P. Dale, Mar 23 2011 *) CROSSREFS Cf. A165451 Sequence in context: A058946 A118379 A174397 * A008709 A008708 A102490 Adjacent sequences:  A173685 A173686 A173687 * A173689 A173690 A173691 KEYWORD nonn,base AUTHOR Michel Lagneau, Nov 25 2010 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .