cp's OEIS Frontend

A135029 Numbers k such that k and k^2 both have digit sum 10. Multiples of 10 are omitted.

%I A135029 #12 Jul 31 2022 07:43:49
%S A135029 19,46,55,145,361,451,20251
%N A135029 Numbers k such that k and k^2 both have digit sum 10. Multiples of 10 are omitted.
%C A135029 A subsequence of A056020. - _R. J. Mathar_, Feb 10 2008
%C A135029 No further terms < 3*10^12 of the form 9*k+1, k=1,2,3,... - _Lars Blomberg_, Jun 28 2011
%C A135029 No further terms < 10^30. - _Charles R Greathouse IV_, Jun 29 2011
%e A135029 Corresponding squares are 361, 2116, 3025, 21025, 130321, 203401, 410103001.
%o A135029 (PARI) dsum(n)=my(s=n%10);while(n\=10,s+=n%10);s
%o A135029 do(L)=my(E,F,G,H,t);for(a=1,L-1, for(b=0,a, for(c=0,b, for(d=0,c, for(e=0,d, E=10^a+10^b+10^c+10^d+10^e; for(f=0,e,F=E+10^f; for(g=0,f, G=F+10^g; for(h=0,g, H=G+10^h; for(i=0,h, t=H+10^i+1; if(dsum(t^2)==10, print1(t", ")))))))))));
%o A135029 do(30) \\ _Charles R Greathouse IV_, Jun 29 2011
%Y A135029 Cf. A056020.
%K A135029 base,nonn
%O A135029 1,1
%A A135029 _Zak Seidov_, Feb 10 2008