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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).
0
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
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.
Sequence in context: A080161 A345405 A257554 * A257787 A098771 A276810
KEYWORD
nonn,more,base
AUTHOR
STATUS
approved