A219906 Number of different straight line programs of length n.

1, 3, 13, 82, 788, 12141, 302791, 11729499

Offset

0,2

Comments

See Borwein and Hobart (or A216999) for definition.

Links

Table of n, a(n) for n=0..7.

Peter Borwein and Joe Hobart, The extraordinary power of division in straight line programs, American Mathematical Monthly 119:7 (2012), pp. 584-592.

Maple

g:= f-> seq([f[], t], t={seq(seq({i+j, i-j, i*j}[], j=f), i=f)}):
F:= proc(n) F(n):= map(g, F(n-1)) end: F(0):= {[1]}:
a:= n-> nops(F(n)):
seq(a(n), n=0..5);  # Alois P. Heinz, Dec 14 2012

Crossrefs

Cf. A173419, A216999, A217032.

Sequence in context: A057993 A208810 A348116 * A000904 A201304 A173998

Adjacent sequences: A219903 A219904 A219905 * A219907 A219908 A219909

Keyword

nonn,more

Author

N. J. A. Sloane, Dec 13 2012

Extensions

Typo in a(4) corrected, a(6)-a(7) from Alois P. Heinz, Dec 14 2012

Status

approved