[seqfan] Sigma(T(n))=T(m)

[zak seidov]

%N Sum of divisors of n-th triangular number is  
m-th triangular number. 
%F Sigma(T(n))=T(m)
%F A000203(A000217(n))=A000217(m)
%Y A000217  Triangular numbers: 
%Y A000203  sigma(n) = sum of divisors of n. 

The first, say, 1000 terms will be greatly appreciated
(private plz).

Thanks,
Zak

n,m
1,1
8,13
9,12
215,384
458,575
520,783
2232,4095
3251,4607
3634,4095
5349,6912
9489,12543
10051,13824
10463,16895
14072,21504
14705,20735
17463,27264
27812,40959
46552,68256
55889,76544
79614,104832
100055,175104
106941,130559
110682,146432
113839,180224
119098,129024
181690,202239
197223,316224
214600,328320
270570,372735
287585,395199
333291,512000
384463,532575
439206,512000
443115,732159
608563,787968
767496,1181439
1097448,1756160
1335300,2253824
1401829,1673216
1471870,1626624
1545794,2037503
1600173,1926144
1617333,1870847
1697586,2121984
1776076,2253824
1841379,2985983
1872262,2024703