

A051045


Number of distinct resistances possible for n resistors with resistances 1, 2, ..., n, each connected in series or parallel to the previous one.


4




OFFSET

1,2


COMMENTS

For n = 4, there would be an additional 4 possible values if circuits were allowed that combine complex subcircuits in series or parallel, rather than requiring that one of them consists of a single resistor. See illustration in links.  Kival Ngaokrajang, Aug 22 2013 (rephrased by Dave R.M. Langers, Nov 13 2013)


LINKS

Table of n, a(n) for n=1..9.
Sean A. Irvine, Java program (github)
Kival Ngaokrajang, Illustration for n = 4
Eric Weisstein's World of Mathematics, Resistor Network.
Index to sequences related to resistances.


CROSSREFS

Cf. A005840.
Sequence in context: A240165 A318977 A111537 * A112912 A303613 A321942
Adjacent sequences: A051042 A051043 A051044 * A051046 A051047 A051048


KEYWORD

nonn,more


AUTHOR

Eric W. Weisstein


EXTENSIONS

Offset corrected and a(8)a(9) from Sean A. Irvine, Aug 23 2021


STATUS

approved



