OFFSET
1,1
COMMENTS
From Altug Alkan, Sep 29 2015: (Start)
Subsequence of A001651.
If a(n)+1 mod 9 != 0 then a(n)-1 mod 9 = 0;
if a(n)-1 mod 9 != 0 then a(n)+1 mod 9 = 0;
a(n)^2 - 1 mod 9 = 0. (End)
A135027(n)*10^k is a term for all n > 0, k >= 0. - Michael S. Branicky, Aug 19 2021
LINKS
Michael S. Branicky, Table of n, a(n) for n = 1..244
Michael S. Branicky, Python program
EXAMPLE
19 is in sequence because 19^2 = 361 and 3+6+1 = 10.
MATHEMATICA
Select[Range[10^5], Total[IntegerDigits[#^2]] == 10 &]
PROG
(Magma) [n: n in [1..3*10^4] | &+Intseq(n^2) eq 10 ];
(PARI) for(n=1, 1e6, if (sumdigits(n^2) == 10, print1(n", "))) \\ Altug Alkan, Sep 28 2015
(Python) # See linked program to go to larger numbers
def ok(n): return sum(map(int, str(n*n))) == 10
print(list(filter(ok, range(25000)))) # Michael S. Branicky, Aug 19 2021
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Vincenzo Librandi, Sep 28 2015
STATUS
approved