The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A323960 Number of defective (binary) heaps on n elements with exactly four defects. 2
 0, 8, 90, 1200, 12502, 111776, 1017060, 8762880, 77887920, 705522048, 6268548000, 60169824000, 543692724960, 5645713615360, 52992483226560, 596317674101760, 5840267078534400, 70071467744931840, 725037082634304000, 9448088175337574400, 100728713738898432000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 4,2 COMMENTS Or number of permutations p of [n] having exactly four indices i in {1,...,n} such that p(i) > p(floor(i/2)). LINKS Alois P. Heinz, Table of n, a(n) for n = 4..200 Eric Weisstein's World of Mathematics, Heap Wikipedia, Binary heap CROSSREFS Column k=4 of A306343. Cf. A056971. Sequence in context: A247728 A056784 A166769 * A187667 A331512 A092956 Adjacent sequences:  A323957 A323958 A323959 * A323961 A323962 A323963 KEYWORD nonn AUTHOR Alois P. Heinz, Feb 09 2019 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified November 26 21:07 EST 2021. Contains 349344 sequences. (Running on oeis4.)