A270393 Another variant of narcissistic numbers: integers n equal the product of squared digits of n divided by the sum of digits of n, i.e., n = A007954(n)^2/A007953(n).

1, 2, 3, 4, 5, 6, 7, 8, 9, 36, 735

Offset

1,2

Comments

No other terms below 10^300. - Max Alekseyev, May 31 2018

Links

Table of n, a(n) for n=1..11.

Example

36 is a term because 36 = (3^2*6^2)/(3+6).
735 is a term because 735 = (7^2*3^2*5^2)/(7+3+5).

Mathematica

Select[Range[10^6], Function[k, k == Apply[Times, #^2]/(Total@ #) &@ IntegerDigits@ k]@ # &] (* Michael De Vlieger, Mar 16 2016 *)

Prog

(PARI) { is_A270393(n) = my(d = digits(n)); n == vecprod(d)^2/vecsum(d); } \\ Michel Marcus, Mar 17 2016

Crossrefs

Subsequence of A128606.

Cf. A005188, A257554.

Sequence in context: A080161 A345405 A257554 * A257787 A098771 A276810

Adjacent sequences: A270390 A270391 A270392 * A270394 A270395 A270396

Keyword

nonn,more,base

Author

José de Jesús Camacho Medina, Mar 16 2016

Status

approved