A068896 -id:A068896 - cp's OEIS frontend

A068898 Triangular numbers containing 2k digits in which the sum of the first k digits = that of the rest.

55, 66, 2415, 3003, 5050, 5151, 5995, 8778, 9045, 113050, 138075, 171405, 174345, 177906, 183921, 198765, 203203, 216153, 219453, 234270, 237705, 239086, 252405, 255255, 266815, 267546, 275653, 279378, 284635, 293761, 294528, 306153, 309291, 329266, 348195

Offset: 1

Amarnath Murthy, Mar 21 2002

			2415 is a term with 2+4 = 1+5.

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Intersection of A000217 and A240927.

Cf. A068896, A068897.

dsQ[n_]:=Module[{idn=IntegerDigits[n],len=IntegerLength[n]/2}, Total[Take[ idn,len]] ==Total[ Take[idn,-len]]]; Select[Flatten[ Table[Table[(n(n+1))/2,{n,Ceiling[(Sqrt[8 10^i+1]-1)/2],Floor[ (Sqrt[8 10^(i+1)+1]-1)/2]}],{i,1,5,2}]],dsQ] (* Harvey P. Dale, Sep 29 2011 *)

Corrected and extended by Harvey P. Dale, Sep 29 2011

Offset changed by Andrew Howroyd, Sep 21 2024

A068897 Squares containing 2k digits in which the sum of the first k digits = that of the rest.

Original entry on oeis.org

5041, 108900, 122500, 128164, 137641, 155236, 173056, 185761, 203401, 206116, 216225, 287296, 288369, 302500, 324900, 342225, 368449, 423801, 434281, 459684, 485809, 515524, 531441, 540225, 675684, 698896, 720801, 737881, 749956, 779689

Offset: 1

Amarnath Murthy, Mar 21 2002

			5041 is a member with 5+0 = 4+1.

Andrew Howroyd, Table of n, a(n) for n = 1..10000

Intersection of A000290 and A240927.

Cf. A068896, A068898.

isok(n)={my(d=digits(n)); my(k=#d); k%2==0 && vecsum(d[1..k/2]) == vecsum(d[k/2+1..k])}
lista(n)={my(L=List(), k=0); while(#LAndrew Howroyd, Sep 19 2024

Corrected and extended by Harvey P. Dale, Mar 31 2002

Offset changed by Andrew Howroyd, Sep 19 2024

cp's OEIS Frontend

A068898 Triangular numbers containing 2k digits in which the sum of the first k digits = that of the rest.

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