Indexing manage_posts_custom_column. This code will add an Index value to each post which is determined by $wp_query->current_post, the number of posts per page, and the current page being viewed.

functions.php

<?php
add_filter( 'manage_posts_columns', 'wpse240648_manage_posts_columns_index');
function wpse240648_manage_posts_columns_index($columns) {
    $columns['index'] = __( 'Index', 'your-text-domain' );
    return $columns;
}

add_action( 'manage_posts_custom_column',  'wpse240648_manage_posts_custom_column_index', 10, 3 );
function wpse240648_manage_posts_custom_column_index( $column, $post_id ) {

    if ( 'index' == $column ) {
        global $wp_query;
        // This line is needed to set up the query so that $wp_query->current_post works.
        $wp_query->the_post();

        $page_number = ( get_query_var( 'paged' ) ) ? get_query_var( 'paged' ) : 0;

        if ( $page_number > 1 ) {
            $current_index = ( $page_number * $wp_query->query_vars['posts_per_page'] ) - $wp_query->query_vars['posts_per_page'];
        } else {
            $current_index = 0;
        }

        echo esc_html( $wp_query->current_post + 1 + $current_index );      
    }
}
?>