A072522 Smallest number a(n)>a(n-1) such that T(a(n-1))+T(a(n))=T(m) for some m, a(1)=3; T(i) are the triangular numbers.
3, 5, 6, 9, 13, 44, 58, 854, 896, 1194, 1253, 1469, 1628, 2170, 2403, 3205, 3366, 3395, 4370, 4454, 4676, 6234, 6545, 6873, 9165, 9624, 12833, 17110, 17450, 18524, 24012, 25025, 25652, 28242, 37657, 356750, 400894, 420938, 561250, 1347002
Offset: 1
Keywords
Links
- Chai Wah Wu, Table of n, a(n) for n = 1..2401
Programs
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PARI
p=3; print1("3, "); for(n=2, 50, t=p*(p+1)/2; for(k=p, 10^9, u=t+k*(k+1)/2; v=floor(sqrt(2*u)); if(v*(v+1)/2==u, print1(k", "); p=k; break)))
Extensions
Edited by Ralf Stephan, Mar 27 2003