A088109 a(1)=1, a(n)= least odd triangular number which is a proper multiple of a(n-1) with a multiplier different from the ones used earlier.

1, 3, 15, 105, 2415, 26565, 1567335, 2785154295, 6918860803558935, 24055444284403886996443725, 332872543972802173225078010738842685950725, 571002075998998180604720399522520480910497598676930064638396594614026468525

Offset

1,2

Links

Table of n, a(n) for n=1..12.

Example

a(2)/a(1) = 3, a(3)/a(2) = 5, a(4)/a(3) = 7, a(5)/a(4) = 23.
a(4) = 105 and not 45, = 3*15.

Crossrefs

Cf. A088108.

Sequence in context: A048599 A129731 A269455 * A231634 A353587 A128276

Adjacent sequences: A088106 A088107 A088108 * A088110 A088111 A088112

Keyword

nonn

Author

Amarnath Murthy, Sep 24 2003

Extensions

More terms from David Wasserman, Jul 20 2005

Status

approved