OFFSET
1,3
EXAMPLE
26569 is in the sequence because (1) it is a square, (2) the sum of its digits is 2+6+5+6+9=28, (3) the product of its digits is 2*6*8*6*9=3240, (4) 28 and 3240 are both triangular numbers.
MATHEMATICA
trnos=Accumulate[Range[0, 1000]];
spdQ[n_]:=Module[{idn=IntegerDigits[n]}, MemberQ[trnos, Total[idn]]&&MemberQ[trnos, Times@@idn]]; Select[Range[0, 650]^2, spdQ] (* Harvey P. Dale, Mar 05 2011 *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Luc Stevens (lms022(AT)yahoo.com), May 05 2006
STATUS
approved