A062036 Positive numbers whose product of digits is four times their sum.

88, 189, 198, 246, 264, 426, 462, 624, 642, 819, 891, 918, 981, 1247, 1274, 1344, 1427, 1434, 1443, 1472, 1724, 1742, 2147, 2174, 2226, 2262, 2417, 2471, 2622, 2714, 2741, 3144, 3414, 3441, 4127, 4134, 4143, 4172, 4217, 4271, 4314, 4341, 4413, 4431

Offset: 1

Author

Amarnath Murthy, Jun 27 2001

Keywords

• nonn
• base
• easy

Examples

			1344 belongs to the sequence as (1*3*4*4)/(1+3+4+4) = 48/12 = 4.
		

Links

• Harry J. Smith, Table of n, a(n) for n = 1..500

Crossrefs

Cf. A011540, A034710, A062034, A062035, A062382, A062037, A062384, A062040, A062041, A062043, A062045.

Programs

Mathematica

p4sQ[n_]:=Module[{idn=IntegerDigits[n]},Times@@idn/Total[idn]==4]; Select[Range[5000],p4sQ]  (* Harvey P. Dale, Apr 26 2011 *)

PARI

isok(n) = my(d=digits(n)); vecprod(d)==4*vecsum(d) \\ Mohammed Yaseen, Jul 31 2022

Python

from math import prod
def ok(n): d = list(map(int, str(n))); return prod(d) == 4*sum(d)
print([k for k in range(1, 5000) if ok(k)]) # Michael S. Branicky, Jul 31 2022

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), Jul 06 2001

Offset corrected by Mohammed Yaseen, Jul 31 2022