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A270537 Numbers that are equal to their number of digits multiplied by the sum the cubes of the digits. 0
1, 2080, 2376, 2580, 3784 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..5.

EXAMPLE

2080 is a term because 2080 = 4 * (2^3 + 0^3 + 8^3 + 0^3);

2376 is a term because 2376 = 4 * (2^3 + 3^3 + 7^3 + 6^3).

MATHEMATICA

Position[ Table[ IntegerLength[ k] Sum[( Floor[k/10^n] - 10 Floor[k/10^(n + 1)])^3, {n, 0, IntegerLength@ k}] - k, {k, 1, 10^6}], 0]

Select[Range[10^5], With[{id=IntegerDigits[#]}, #==Length[id]*Plus@@(id^3)]&] (* Ray Chandler, Apr 01 2016 *)

PROG

(PARI) isok(n) = my(d=digits(n)); n == #d*sum(k=1, #d, d[k]^3); \\ Michel Marcus, Mar 25 2016

CROSSREFS

Sequence in context: A076425 A249654 A180921 * A076581 A183675 A178272

Adjacent sequences:  A270534 A270535 A270536 * A270538 A270539 A270540

KEYWORD

nonn,base,fini,full

AUTHOR

José de Jesús Camacho Medina, Mar 18 2016

STATUS

approved

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Last modified June 28 12:00 EDT 2022. Contains 354907 sequences. (Running on oeis4.)