

A309884


Numbers k such that A003132(k^3) = A003132(k), where A003132(n) is the sum of the squares of the digits of n.


1



0, 1, 10, 74, 100, 740, 1000, 3488, 7400, 10000, 23658, 30868, 34880, 47508, 48517, 52187, 58947, 59468, 67685, 68058, 74000, 76814, 78368, 78845, 84878, 100000, 108478, 145877, 149217, 163871, 179685, 186884, 188647, 218977, 219878, 236580, 238758, 248967, 278638, 292597, 308680
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,3


COMMENTS

If k is in the sequence, then so are k*10^r, with r >= 1.


LINKS

Table of n, a(n) for n=1..41.


EXAMPLE

74^3 = 405224, A003132(74) = 7^2 + 4^2 = 65, A003132(405224) = 4^2 + 0^2 + 5^2 + 2^2 + 2^2 + 4^2 = 65.


MATHEMATICA

digSum[n_] := Total[IntegerDigits[n]^2]; Select[Range[0, 310000], digSum[#] == digSum[#^3] &] (* Amiram Eldar, Aug 22 2019 *)


PROG

(PARI) for(i = 0, 400000, if(norml2(digits(i^3)) == norml2(digits(i)), print1(i, ", ")))
(MAGMA) [0] cat [k:k in [1..310000] &+[c^2: c in Intseq(k)] eq &+[c^2: c in Intseq(k^3)]]; // Marius A. Burtea, Aug 26 2019


CROSSREFS

Cf. A003132, A058369, A070276, A174460, A176670, A178213, A307735, A309883.
Sequence in context: A199556 A044197 A044578 * A279284 A264082 A103434
Adjacent sequences: A309881 A309882 A309883 * A309885 A309886 A309887


KEYWORD

nonn,base


AUTHOR

Antonio Roldán, Aug 21 2019


STATUS

approved



