[seqfan] Possible error in A190660

Jeremy Gardiner jeremy.gardiner at btinternet.com
Sat Aug 10 16:12:40 CEST 2013


A190660 Number of triangular numbers T(k) between powers of 2, 2^(n-1) <
T(k) <= 2^n
1, 0, 1, 1, 2, 2, 3, 5, 7, 9, 13, 19, 27, 37, 53, 75, 106, 150, ...

I calculate:
1, 0, 1, 1, 1, 2, 2, 3, 5, 7, 9, 13, 19, 27, 37, 53, 75, 106, 150, ...

Being first differences of A(n) = round(sqrt(2)^n), n = 0,1,...

A(n) = 1, 1, 2, 3, 4, 6, 8, 11, 16, 23, 32, 45, 64, 91, 128, 181

Cf. A057048

- Please can someone verify?

Thanks,
Jeremy





More information about the SeqFan mailing list