67896

Appears in sequences

• Smallest triangular number with digit sum n (or 0 if no such number exists).at n=35A062688
• Triangular numbers not divisible by 10 whose reverse is pentagonal.at n=5A066758
• Duplicate of A062688.at n=36A067181
• First triangular number with digit sum = n-th triangular number.at n=8A068133
• Triangular numbers with property that digits alternate in parity individually as well as in concatenation with previous terms.at n=21A068889
• Triangular numbers which are 7-almost primes.at n=23A076581
• Triangular numbers whose digit reversal is a pentagonal number (A000326).at n=6A115682
• Triangular numbers for which the sum of the digits is a square.at n=23A117404
• Numerators of expansion of eta(5t)^2*eta(10t)^(13/5)*eta(20t)^(-9/5)*eta(40t)^(6/5).at n=62A135468
• Number x such that x | A255242(x).at n=26A255243
• Lexicographically first sequence of distinct terms such that any set of four successive digits can be reordered as {d, d+1, d+2, d+3}, d being the smallest of the four digits.at n=54A302499
• Triangular numbers such that the three numbers before it and the three numbers after it are squarefree.at n=11A374393
• Positive triangular numbers such that the two numbers before it and the two numbers after it are squarefree.at n=43A374503