command line - inserting few copies of the same page into PDF - Ask Ubuntu

i want insert x blank pages pdf document. can pdftk :

pdftk a=book.pdf b=page.pdf cat a1-end b output output.pdf 

when want insert more 1 page, can that:

pdftk a=book.pdf b=page.pdf cat a1-end b b b output output.pdf 

is there syntax allows insert x pages without repeating same parameter in command line?