A262569 a(n) = (A002703(n)+2)/2.

1, 1, 1, 2, 4, 8, 13, 24, 45, 82, 151, 282, 529, 992, 1872, 3542, 6720, 12788, 24385, 46600, 89241, 171197, 328960, 633102, 1220160, 2354688, 4549753, 8801162, 17043506, 33038208, 64103989, 124491776, 241969989, 470681348, 916259632, 1784921474, 3479467177, 6787108713, 13247128045, 25870861824, 50552258560, 98832505868

Offset

3,4

Comments

All of A002703, A262567, A262568 and this sequence are somewhat mysterious, so having four versions instead of one increases the chance that one of them will be found in a different context.

Links

Table of n, a(n) for n=3..44.

Alexander Rosa and Štefan Znám, A combinatorial problem in the theory of congruences. (Russian), Mat.-Fys. Casopis Sloven. Akad. Vied 15 1965 49-59. [Annotated scanned copy]

Formula

a(n) = A262568(n)/2 = A262567(n) + 1.

Maple

See A262568.

Crossrefs

Cf. A002703, A252567, A262568.

Tables 1 and 2 of the first Rosa-Znám 1965 paper are A053632 and A178666 respectively.

Sequence in context: A000077 A054164 A226060 * A248876 A102704 A196720

Adjacent sequences: A262566 A262567 A262568 * A262570 A262571 A262572

Keyword

nonn

Author

N. J. A. Sloane, Oct 20 2015

Extensions

More terms from R. J. Mathar, Oct 21 2015

Status

approved