33930

Appears in sequences

• Coefficient of x^4 in (1-x-x^2)^(-n).at n=25A006504
• Matrix 9th power of partition triangle A008284.at n=37A050303
• Composite numbers k such that the difference between the odd and even aliquot parts of k divides k.at n=28A066193
• Triangular numbers which are products of triangular numbers larger than 1.at n=28A068143
• a(n) = smallest triangular number having no digit in common with the previous term, with a(1) = 1.at n=27A068818
• Triangular numbers which are the sum of two squares.at n=36A073613
• Triangular numbers whose sum of prime factors (with repetition) is also triangular.at n=24A076169
• Triangular numbers which are 6-almost primes.at n=23A076580
• Triangular numbers that are 5 times another triangular number.at n=4A077261
• Triangular numbers using only the curved digits 0, 3, 6, 8 and 9.at n=12A079653
• Triangular numbers for which the sum of the digits is a heptagonal number.at n=30A117312
• Triangular numbers for which the sum of the digits equals the sum of the digits of the next triangular number.at n=12A117511
• Triangular numbers composed of digits {0,3,9}.at n=5A119069
• Triangular numbers that are the product of two triangular numbers greater than 1.at n=20A188630
• a(n) = lcm(n,n+1,n+2,n+3,n+4,n+5,n+6)/420.at n=24A189144
• Number of ways to place n nonattacking composite pieces rook + rider[1,3] on an n X n chessboard.at n=9A189850
• Values of the difference d for 6 primes in arithmetic progression with the minimal start sequence {7 + j*d}, j = 0 to 5.at n=12A206040
• Triangular numbers that are the product of a triangular number and a prime number.at n=48A253651
• Positive numbers m such that m^2 - 1 divides 4^m - 1.at n=22A271842
• Triangle read by rows. A generalization of unsigned Lah numbers, called L[3,1].at n=63A290596