Suppressing Page numbers

[Jonathan Wilkes]

Hello,
     I'm trying to finish up a score and am doing something 
fairly standard:
page 1: title (no page#)
page 2: blank (no page#)
page 3: "Notes" (no page#)
page 4: music (numbered as page #1)

I've seen a scheme function to suppress the first two pages, and a 
command to renumber pages, but I can't figure out how to use the two 
in tandem.

What would be great is just a single command to keep from printing 
negative page numbers.

Here's my snippet:

\version "2.12.2"

\include "titling-init.ly"

#(define (skip-two-page-numbers layout props arg)
  (if (or (> (chain-assoc-get 'page:page-number props -1) 
             (+ (ly:output-def-lookup layout 'first-page-number) 1))
          (eq? (ly:output-def-lookup layout 'print-first-page-number) #t))
      (create-page-number-stencil layout props arg)
      empty-stencil))

\markup Title
\pageBreak
\markup " "
\pageBreak
\markup { \fill-line { "Notes" } }
\pageBreak

\score {
        c d e f
}

\paper {
  first-page-number = #-2
  oddHeaderMarkup = \markup
  \fill-line {
    " "
    \on-the-fly #not-first-page \fromproperty #'header:instrument
    \on-the-fly #skip-two-page-numbers \fromproperty #'page:page-number-string
  }
  evenHeaderMarkup = \markup
  \fill-line {
    \on-the-fly #skip-two-page-numbers \fromproperty #'page:page-number-string
    \on-the-fly #not-first-page \fromproperty #'header:instrument
    " "
  }

}