1851850

Appears in sequences

• Triangular numbers whose digit reversal is also a triangular number.at n=35A061455
• Nonpalindromic triangular numbers whose digit reversal is also a triangular number (possibly with fewer digits).at n=17A069673
• Triangular numbers k such that phi(k) is a square number, where phi(k) is the Euler totient function (A000010).at n=32A287473