# [JavaScript (Node.js)], 71 bytes <!-- language-all: lang-javascript --> n=>[...(m=Array(n)).keys()].map(a=>[...m.keys()].map(b=>-~a>++b?-~a:b)) [Try it online!][TIO-kpr8mk8r] [JavaScript (Node.js)]: https://nodejs.org [TIO-kpr8mk8r]: https://tio.run/##y0osSyxOLsosKNHNy09J/Z9m@z/P1i5aT09PI9fWsagosVIjT1NTLzu1slhDM1YvN7FAIxEin4simGRrp1uXaKetnWQPpK2SNDX/J@fnFefnpOrl5KdrpGlYAEUA "JavaScript (Node.js) – Try It Online" Outputs an array of arrays. # [JavaScript (Node.js)], 87 bytes <!-- language-all: lang-javascript --> n=>[...(m=Array(n)).keys()].map(a=>[...m.keys()].map(b=>-~a>++b?-~a:b).join` `).join` ` [Try it online!][TIO-kpr8pt7s] [JavaScript (Node.js)]: https://nodejs.org [TIO-kpr8pt7s]: https://tio.run/##y0osSyxOLsosKNHNy09J/Z9m@z/P1i5aT09PI9fWsagosVIjT1NTLzu1slhDM1YvN7FAIxEin4simGRrp1uXaKetnWQPpK2SNPWy8jPzEhQSoAyuhP/J@XnF@Tmpejn56RppGhaamv8B "JavaScript (Node.js) – Try It Online" Output as a string