43071

Appears in sequences

• Expansion of 1/((1-2x)(1-3x)(1-5x)(1-11x)).at n=4A025935
• Odd triangular numbers with prime indices.at n=29A034954
• Triangular numbers whose digit permutations yield at least two further triangular numbers.at n=24A069674
• a(n) is the smallest number m such that for the n-digit number s=10^(n-1)+ m, 10*s+1, 10*s+3, 10*s+7 and 10*s+9 are primes.at n=17A097639
• Hexagonal numbers for which the sum of the digits is also a hexagonal number.at n=31A117062
• Hexagonal numbers for which both the sum of the digits and the product of the digits are also hexagonal numbers.at n=18A117064
• Triangular numbers p*(p+1)/2 with p prime such that 1+(number of prime factors of p+1) is prime.at n=25A144549
• Cyclops triangular numbers.at n=12A160717
• Triangular numbers which have one or more occurrences of exactly five different digits.at n=33A241788
• Integers of the form 8k+7 that can be written as a sum of four distinct squares of the form m, m+2, m+4, m+5, where m == 1 (mod 4).at n=25A243579
• Number of distinct lines passing through at least two points in a triangular grid of side n.at n=27A244504
• Triangular numbers n with digits d_1, d_2, ..., d_k such that d_1*(d_1+1)/2 + ... + d_k*(d_k+1)/2 is a triangular number.at n=35A254957
• Triangular numbers T(i) that can be expressed as the sum of 2 positive triangular numbers, T(j)+T(k), and for which i+j+k is a triangular number, where T is A000217.at n=5A343426