A348240 a(n) = Sum_{k = 0..floor(n/2)} A003041(n-2*k).

1, 2, 8, 26, 100, 414, 1980, 11014, 73412, 598666, 6102526, 79159950, 1326445684, 29043841986, 838338488166, 32103913567002, 1639094610080320, 111984620680187738, 10269822211032260280, 1267351723826564990690, 210933562074090864494452, 47439657241536467554526958, 14443894335766431753573544432, 5963049049052361028967102180434

Offset

0,2

Links

Table of n, a(n) for n=0..23.

H. Sharp, Jr., Enumeration of vacuously transitive relations, Discrete Math. 4 (1973), 185-196.

Crossrefs

Cf. A003041.

Sequence in context: A129368 A357221 A281345 * A128238 A385041 A110156

Adjacent sequences: A348237 A348238 A348239 * A348241 A348242 A348243

Keyword

nonn

Author

N. J. A. Sloane, Oct 13 2021

Extensions

Offset corrected and terms a(5) onward added by Max Alekseyev, Apr 01 2026

Status

approved