A290934 a(n) equals the sum of the squares of the digits of A254958(n).

1, 4, 9, 16, 25, 36, 49, 64, 81, 25, 25, 100, 100, 9, 81, 81, 9, 9, 49, 36, 49, 121, 121, 49, 49, 81, 81, 36, 36, 81, 81, 81, 144, 49, 121, 49, 81, 81, 121, 121, 121, 81, 121, 81, 81, 144, 144, 121, 121, 4, 36, 36, 100, 25, 25, 36, 100, 36, 100, 25, 49, 36, 36

Offset: 1

Author

Jonathan Schwartz, Aug 14 2017

Keywords

• nonn
• base

Links

• Jonathan Schwartz, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000290, A003132, A254958.

Programs

Java

import java.util.ArrayList;public class Seq {public static void main(String[] args) {int l = 1000;
ArrayList squares = new ArrayList();
for (int i = 1; i <= l; i++) {squares.add((i * i));}
int term = 1;
for (int n = 1; n < Integer.MAX_VALUE; n++) {
if (!(Integer.toString(n).contains("0")))
if (squares.contains(sum(n))){
int k = 0;
for(int i = 0;i1000)break;}}
static int sum(int n) {int s = 0;String str = Integer.toString(n);for (int i = 0; i < str.length(); i++) {s += (Integer.valueOf(Character.toString(str.charAt(i)))*Integer.valueOf(Character.toString(str.charAt(i))));}return s;}}

Mathematica

Select[Map[Total, Select[Array[IntegerDigits, 1550], FreeQ[#, 0] &]^2], IntegerQ@ Sqrt@ # &] (* Michael De Vlieger, Aug 15 2017 *)

PARI

lista(nn) = {for (n=1, nn, d = digits(n); if (vecmin(d) && issquare(s=sum(k=1, #d, d[k]^2)), print1(s, ", ")););} \\ Michel Marcus, Aug 28 2017