A225535 - OEIS

A225535

Numbers whose cubed digits sum to a cube, and have more than one nonzero digit.

168, 186, 345, 354, 435, 453, 534, 543, 618, 681, 816, 861, 1068, 1086, 1156, 1165, 1516, 1561, 1608, 1615, 1651, 1680, 1806, 1860, 3045, 3054, 3405, 3450, 3504, 3540, 4035, 4053, 4305, 4350, 4503, 4530, 5034, 5043, 5116, 5161, 5304, 5340, 5403, 5430, 5611

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OFFSET

1,1

LINKS

Christian N. K. Anderson, Table of n, a(n) for n = 1..10000

EXAMPLE

5^3 + 6^3 + 1^3 + 1^3 = 343, which is 7^3.

MATHEMATICA

fQ[n_] := Module[{d = IntegerDigits[n]}, Count[d, 0] + 1 < Length[d] && IntegerQ[Total[d^3]^(1/3)]]; Select[Range[5611], fQ] (* T. D. Noe, May 19 2013 *)

PROG

(R)y=rep(0, 10000); len=0; x=0; library(gmp);

digcubesum<-function(x) sum(as.numeric(unlist(strsplit(as.character(as.bigz(x)), split="")))^3);

iscube<-function(x) ifelse(as.bigz(x)<2, T, all(table(as.numeric(factorize(x)))%%3==0));

nonzerodig<-function(x) sum(strsplit(as.character(x), split="")[[1]]!="0");

which(sapply(1:6000, function(x) nonzerodig(x)>1 & iscube(digcubesum(x))))

CROSSREFS

Cf. A225534 (cubed digits sum to a prime), A197039 (square), A046459. A055012.

Cf. A165330 (cube cycle), A046197 (cubic fixed points), A000578 (cubes).

Cf. A052034 (squared digits sum to a prime), A028839, A117685.

Cf. A164882 (n such that sum of the cubes of the digits of n^3 is perfect cube). - Zak Seidov, May 21 2013

Sequence in context: A062518 A038823 A296890 * A333874 A045242 A117529

Adjacent sequences: A225532 A225533 A225534 * A225536 A225537 A225538

KEYWORD

nonn,base

AUTHOR

Kevin L. Schwartz and Christian N. K. Anderson, May 10 2013

STATUS

approved