A062331 a(n) is the product of the sum and the product of the digits of n (0 is not to be considered a factor in the product).

1, 4, 9, 16, 25, 36, 49, 64, 81, 1, 2, 6, 12, 20, 30, 42, 56, 72, 90, 4, 6, 16, 30, 48, 70, 96, 126, 160, 198, 9, 12, 30, 54, 84, 120, 162, 210, 264, 324, 16, 20, 48, 84, 128, 180, 240, 308, 384, 468, 25, 30, 70, 120, 180, 250, 330, 420, 520, 630, 36, 42, 96, 162, 240, 330

Offset: 1

Author

Amarnath Murthy, Jun 21 2001

Keywords

• nonn
• easy
• base

Examples

			a(49) = (4+9)*(4*9) = 13*36 = 458.
		

Links

• Alois P. Heinz, Table of n, a(n) for n = 1..10000 (first 1000 terms from Harry J. Smith)

Crossrefs

Cf. A007953, A051801.

Programs

Maple

a:= n-> (l-> add(i, i=l)*mul(`if`(i=0, 1, i), i=l))(convert(n, base, 10)):
seq(a(n), n=1..100);  # Alois P. Heinz, Jun 29 2018

Mathematica

psd[n_]:=Module[{idnx0=Select[IntegerDigits[n],#>0&]},Times@@idnx0  Total[idnx0]]
psd/@Range[90]  (* Harvey P. Dale, Feb 24 2011 *)
Array[Times @@ DeleteCases[#, 0]*Total@ # &@ IntegerDigits[#] &, 65] (* Michael De Vlieger, Jun 29 2018 *)

PARI

a(n) = sumdigits(n) * vecprod(select(t->t, digits(n))) \\ Harry J. Smith, Aug 05 2009

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), Jun 22 2001