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A327235 Number of unlabeled simple graphs with n vertices whose edge-set is not connected. 4
1, 1, 1, 1, 2, 4, 14, 49, 234, 1476, 15405, 307536, 12651788, 1044977929, 167207997404, 50838593828724, 29156171171238607, 31484900549777534887, 64064043979274771429379, 246064055301339083624989655 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

LINKS

Table of n, a(n) for n=0..19.

FORMULA

a(n) = 1 + A000088(n) - Sum_{i = 1..n} A001349(i).

EXAMPLE

The a(4) = 2 through a(6) = 14 edge-sets:

  {}       {}             {}

  {12,34}  {12,34}        {12,34}

           {12,35,45}     {12,34,56}

           {12,34,35,45}  {12,35,45}

                          {12,34,35,45}

                          {12,35,46,56}

                          {12,36,46,56}

                          {13,23,46,56}

                          {12,34,35,46,56}

                          {12,36,45,46,56}

                          {13,23,45,46,56}

                          {12,13,23,45,46,56}

                          {12,35,36,45,46,56}

                          {12,34,35,36,45,46,56}

CROSSREFS

Unlabeled non-connected graphs are A000719.

Partial sums of A327075.

The labeled version is A327199.

Cf. A000088, A001349, A002494, A052446, A054592, A327070, A327071.

Sequence in context: A212268 A092665 A046650 * A055727 A003500 A316363

Adjacent sequences:  A327232 A327233 A327234 * A327236 A327237 A327238

KEYWORD

nonn

AUTHOR

Gus Wiseman, Sep 01 2019

STATUS

approved

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Last modified August 14 09:14 EDT 2020. Contains 336480 sequences. (Running on oeis4.)