A051045 - OEIS

A051045

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

1, 2, 8, 44, 298, 2350, 22774, 252079, 3154451

(list; graph; refs; listen; history; text; internal format)

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: A357832 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