{"id":474513,"date":"2026-05-14T19:36:00","date_gmt":"2026-05-14T19:36:00","guid":{"rendered":"https:\/\/livelycity.com\/switzerland\/1-2-3-4-%e2%8b%af-%e2%8b%af-wikipedia\/"},"modified":"2026-05-14T19:36:00","modified_gmt":"2026-05-14T19:36:00","slug":"1-2-3-4-%e2%8b%af-%e2%8b%af-wikipedia","status":"publish","type":"post","link":"https:\/\/livelycity.com\/switzerland\/1-2-3-4-%e2%8b%af-%e2%8b%af-wikipedia\/","title":{"rendered":"1 + 2 + 3 + 4 + \u22ef &#8211; \u22ef &#8211; Wikipedia"},"content":{"rendered":"<p>The partial sums of the series 1 + 2 + 3 + 4 + 5 + 6 + \u22ef are 1, 3, 6, 10, 15, etc. The n th partial sum is given by a simple formula: This equation was known to the Pythagoreans as early as the sixth century BCE. [5] Numbers of this form are called triangular numbers, because they can be arranged as an equilateral triangle.<\/p>\n<p>\u00a0<a href=\"https:\/\/en.wikipedia.org\/wiki\/1_%2B_2_%2B_3_%2B_4_%2B_%E2%8B%AF\" target=\"_blank\" class=\"\">https:\/\/en.wikipedia.org\/wiki\/1_%2B_2_%2B_3_%2B_4_%2B_%E2%8B%AF<\/a>\u00a0<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The partial sums of the series 1 + 2 + 3 + 4 + 5 + 6 + \u22ef are 1, 3, 6, 10, 15,&#8230;<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[8],"tags":[],"class_list":["post-474513","post","type-post","status-publish","format-standard","hentry","category-zurich","wpcat-8-id"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/livelycity.com\/switzerland\/wp-json\/wp\/v2\/posts\/474513","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/livelycity.com\/switzerland\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/livelycity.com\/switzerland\/wp-json\/wp\/v2\/types\/post"}],"replies":[{"embeddable":true,"href":"https:\/\/livelycity.com\/switzerland\/wp-json\/wp\/v2\/comments?post=474513"}],"version-history":[{"count":0,"href":"https:\/\/livelycity.com\/switzerland\/wp-json\/wp\/v2\/posts\/474513\/revisions"}],"wp:attachment":[{"href":"https:\/\/livelycity.com\/switzerland\/wp-json\/wp\/v2\/media?parent=474513"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/livelycity.com\/switzerland\/wp-json\/wp\/v2\/categories?post=474513"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/livelycity.com\/switzerland\/wp-json\/wp\/v2\/tags?post=474513"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}