OFFSET
1,2
LINKS
Harry J. Smith, Table of n, a(n) for n = 1..1000
EXAMPLE
144 belongs to the sequence as sum of digits = 9 and the product of the digits = 16.
MATHEMATICA
pdsdQ[n_]:=Module[{idn=IntegerDigits[n]}, IntegerQ[Sqrt[Total[idn]]] && IntegerQ[Sqrt[Times@@idn]]]; Select[Range[1100], pdsdQ] (* Harvey P. Dale, Aug 20 2012 *)
PROG
(PARI) SumD(x)= { s=0; while (x>9, s+=x-10*(x\10); x\=10); return(s + x) } ProdD(x)= { p=1; while (x>9, p*=(x-10*(x\10)); x\=10); return(p*x) } { n=0; for (m=1, 10^9, if (issquare(ProdD(m)) && issquare(SumD(m)), write("b062398.txt", n++, " ", m); if (n==1000, break)) ) } \\ Harry J. Smith, Aug 07 2009
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Amarnath Murthy, Jun 28 2001
EXTENSIONS
Corrected and extended by Erich Friedman, Jul 02 2001
STATUS
approved