A173799 Partial sums of A019318.

1, 3, 19, 271, 7085, 251429, 10997806, 564316854, 33175912910, 2196968168590, 161790768056642, 13114202824936638, 1160158996141467678, 111226473580172327222, 11486922450679555836573

Offset

1,2

Comments

Partial sums of number of inequivalent ways of choosing n squares from an n X n board, considering rotations and reflections to be the same.The subsequence of primes in this partial sum (unexpectedly dense at first) begins: 3, 19, 271, 251429, no more through a(20) yet 4 of the first 5 values after a(1).

Links

Table of n, a(n) for n=1..15.

Formula

a(n) = SUM[i=1..n] A019318(i) = SUM[i=1..n] {number of inequivalent ways of choosing i squares from an i X i board, considering rotations and reflections to be the same}.

Example

a(6) = 1 + 2 + 16 + 252 + 6814 + 244344 = 251429 is prime.

Crossrefs

Cf. A019318, A054252, A014409.

Sequence in context: A356672 A316294 A233240 * A003011 A338772 A231620

Adjacent sequences: A173796 A173797 A173798 * A173800 A173801 A173802

Keyword

nonn

Author

Jonathan Vos Post, Feb 25 2010

Status

approved