A101756 Number of divisors of highly composite triangular numbers.

1, 2, 4, 6, 9, 16, 18, 20, 24, 36, 40, 48, 90, 112, 128, 144, 162, 168, 192, 240, 320, 480, 576, 648, 768, 1024, 1280, 1344, 1512, 1536, 1728, 1920, 2304, 2880, 3072, 3200, 3456, 3888, 4480, 5760, 6144, 6912, 7680, 8640, 9216, 13824, 16128, 23040, 25088

Offset

1,2

Links

Charles R Greathouse IV and Donovan Johnson, Table of n, a(n) for n = 1..70 (first 55 terms from Charles R Greathouse IV).

Formula

a(n) = A000005(A076711(n)) = A000005(A000217(A101755(n))).

Prog

(PARI) t1=1; r=0; for(n=1, 2e9, t2=n+1; t2=numdiv(t2/if(n%2, 2, 1)); if(t1*t2>r, r=t1*t2; print1(r", ")); t1=t2) \\ Charles R Greathouse IV, Feb 01 2013

Crossrefs

Cf. A076711, A101755.

Sequence in context: A074677 A006498 A179997 * A350552 A352359 A372542

Adjacent sequences: A101753 A101754 A101755 * A101757 A101758 A101759

Keyword

nonn

Author

Ray Chandler, Dec 22 2004

Status

approved