Putin didn’t go, he sent the speaker of the upper house. Supposedly Putin was preparing for a state of the union address and he visited the embassy in Russia and signed a book of condolences.
The list of those not in attendance-
President Omar al-Bashir (Sudan)
President Adly Mansour (Egypt)
Prime Minister Jiri Rusnok (Czech)
Prime Minister Benjamin Netanyahu (Israel)
President Hassan Rouhani (Iran)
President Xi Jinping (China)
President Vladimir Putin (Russia)
He couldn't come up with a better excuse than that? Here are some suggestions:
He had just fixed a bowl of cornflakes and had to eat them before they got soggy.
He just took a shower and wasn't dry yet.
His bag of M and M's didn't have any blue ones and he had to file a complaint with Mars.