70125

Appears in sequences

• Triangular numbers which are products of triangular numbers larger than 1.at n=37A068143
• Triangular numbers with property that digits alternate in parity individually as well as in concatenation with previous terms.at n=22A068889
• Row sums in A100781.at n=32A100784
• Partition number array, called M32(-5), related to A013988(n,m)= |S2(-5;n,m)| ( generalized Stirling triangle).at n=20A144268
• a(n) = smaller member of n-th pair of distinct, positive, triangular numbers whose sum and difference are also triangular numbers.at n=10A185129
• a(n) = m*(m+1)/2, where m = floor(n^(3/2)).at n=51A185541
• Triangular numbers that are the product of two triangular numbers greater than 1.at n=26A188630
• Triangular numbers T from A000217 such that (4*T+1)/13 is prime.at n=21A208294
• Triangular numbers representable as t*p, where t>1 is a triangular number, p>1 is a prime power (A025475).at n=5A221563
• Triangular numbers which are an average of four consecutive primes.at n=34A226196
• Odd numbers that are not of the form p + 2^a + 2^b with b > a > 0, and p prime.at n=12A268693
• Triangular numbers k such that psi(k) is a square, where psi(k) is the Dedekind psi function (A001615).at n=24A292064
• Triangular numbers that can be represented as a sum of two distinct triangular numbers, and as a product of two triangular numbers greater than 1.at n=11A295768
• Numbers that are product of a second hexagonal number (A014105) and a square pyramidal numbers (A000330) in at least two ways.at n=13A306122
• Coefficients T(n,k) of x^n*y^(n-k)*z^k in function A = A(x,y,z) such that A = 1 + x*B*C, B = 1 + y*C*A, and C = 1 + z*A*B, as a triangle read by rows.at n=57A323324
• Coefficients T(n,k) of x^n*y^(n-k)*z^k in function A = A(x,y,z) such that A = 1 + x*B*C, B = 1 + y*C*A, and C = 1 + z*A*B, as a triangle read by rows.at n=63A323324
• Numbers that start a run of four consecutive triangular numbers with four distinct prime factors.at n=12A349773