303031

Appears in sequences

• Triangular numbers with every digit a triangular number.at n=20A062100
• Triangular numbers whose reverse is prime.at n=33A066751
• a(1) = 1; a(n) is the smallest triangular number > a(n-1) which differs from it at every digit.at n=39A068855
• Triangular numbers composed of digits {0,1,3}.at n=6A119035
• Pseudoprimes to base 4, written in base 4.at n=24A262101
• Expansion of x^2*(10-5*x+x^2)/((1-x)^4*(1-x^2)).at n=38A331429