%I #31 Jul 16 2022 22:52:14
%S 1,4,9,16,25,36,49,64,81,0,2,6,12,20,30,42,56,72,90,0,6,16,30,48,70,
%T 96,126,160,198,0,12,30,54,84,120,162,210,264,324,0,20,48,84,128,180,
%U 240,308,384,468,0,30,70,120,180,250,330,420,520,630,0,42,96,162,240,330
%N a(n) = (sum of digits of n) * (product of digits of n).
%C a(n) can be greater than, less than, or equal to n; see Example section.
%H Harry J. Smith, <a href="/A066308/b066308.txt">Table of n, a(n) for n = 1..1000</a>
%e For n = 12, a(12) = (1 + 2)*(1*2) = 3*2 = 6 < n;
%e for n = 19, a(19) = (1 + 9)*(1*9) = 90 > n;
%e for n = 135, a(135) =(1 + 3 + 5)*(1*3*5) = 135 = n.
%t asum[x_] := Apply[Plus, IntegerDigits[x]] apro[x_] := Apply[Times, IntegerDigits[x]] a[n]=asum[n]*apro[n]
%t sdpd[n_]:=Module[{idn=IntegerDigits[n]},Total[idn]Times@@idn]; Array[ sdpd,70] (* _Harvey P. Dale_, Dec 31 2011 *)
%o (PARI) SumD(x)= { local(s=0); while (x>9, s+=x%10; x\=10); return(s + x) }
%o ProdD(x)= { local(p=1); while (x>9 && p>0, p*=x%10; x\=10); return(p*x) }
%o { for (n=1, 1000, a=SumD(n)*ProdD(n); write("b066308.txt", n, " ", a) ) } \\ _Harry J. Smith_, Feb 09 2010
%o (PARI) a(n) = my(d = digits(n)); vecsum(d) * prod(k=1, #d, d[k]); \\ _Michel Marcus_, Feb 24 2017
%Y Cf. A007953, A007954.
%Y Cf. A038369 (fixed points), A034710, A061672.
%Y Cf. A049101, A049102, A049103, A049104, A049105, A049106.
%K base,easy,nonn
%O 1,2
%A _Labos Elemer_, Dec 13 2001
%E Edited by _Jon E. Schoenfield_, Jul 09 2018