A219906 Number of different straight line programs of length n.

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

Offset: 0

Author

N. J. A. Sloane, Dec 13 2012

Keywords

• nonn
• more

Comments

See Borwein and Hobart (or A216999) for definition.

Links

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

Crossrefs

Cf. A173419, A216999, A217032.

Programs

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

Extensions

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