login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 


a(0)=0; a(n) is the smallest m such that m - a(i) is not a triangular number for any i < n.
3

%I #17 Oct 05 2020 15:48:49

%S 0,2,4,9,11,13,18,20,22,27,29,31,51,53,60,62,69,71,85,94,101,103,110,

%T 112,141,143,150,152,159,161,168,170,211,220,229,245,267,269,292,299,

%U 301,308,310,317,319,326,348,357,359,366,368,375,418,427,456,458,499,508

%N a(0)=0; a(n) is the smallest m such that m - a(i) is not a triangular number for any i < n.

%D A. Sárközy. On the difference sets of sequences of integers II, Ann. Univ. Sci. Budapest. Eotvos Sect. Math. 21(1978), 45-53.

%H Hugo Pfoertner, <a href="/A030194/b030194.txt">Table of n, a(n) for n = 0..10000</a>

%H I. Ruzsa, <a href="http://dx.doi.org/10.1007/BF02454169">Difference sets without squares</a>, Period. Math. Hungar. 15 (1984), no. 3, 205-209.

%H A. Sárközy, <a href="http://dx.doi.org/10.1007/BF01896079">On difference sets of sequences of integers I</a>, Acta Mathematica Academiae Scientiarum Hungarica, March 1978, Volume 31, Issue 1, pp 125-149.

%H A. Sárközy, <a href="http://dx.doi.org/10.1007/BF01901984">On difference sets of sequences of integers III</a>, Acta Mathematica Academiae Scientiarum Hungarica, September 1978, Volume 31, Issue 3, pp 355-386.

%o (PARI) a030194(upto)={my(a=vector(upto));a[1]=2;for(n=2,upto,for(m=a[n-1]+1,oo,my(f=1);for(j=1,n,if(ispolygonal(m-a[j],3),f=0;break));if(f,a[n]=m;break)));concat([0],a)};

%o a030194(57) \\ _Hugo Pfoertner_, Oct 05 2020

%Y Cf. A000217, A082183, A336531.

%K nonn

%O 0,2

%A _Jan Kristian Haugland_

%E Name edited by _Michel Marcus_, Oct 05 2020

%E More terms from _Hugo Pfoertner_, Oct 05 2020

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 23 13:52 EDT 2024. Contains 376171 sequences. (Running on oeis4.)