100172

Appears in sequences

• s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (Lucas numbers), t = A001950 (upper Wythoff sequence).at n=27A025095
• Numbers k such that k | sigma_13(k) - phi(k)^13.at n=26A055707
• Numbers k such that 210*k+{11, 13, 17, 19, 23, 29} are 6 consecutive primes.at n=26A182282
• Numbers k such that 210*k+{11,13,17,19,23,29,31} are 7 consecutive primes.at n=6A182387
• Number of acute triangles, distinct up to congruence, on an n X n grid (or geoboard).at n=36A190021
• Number of times the digit 9 appears in the first 10^n digits of Catalan's constant.at n=5A224818
• Numbers <= 10^6 with valid Luhn mod 10 check digit, sorted lexicographically.at n=20A249854
• Numbers n such that 2 * (1^n + 2^n + 3^n + ... + n^n) is not 0 (mod n), but 2 * (1^d + 2^d + 3^d + ... + d^d) is 0 (mod d) for each other d | n.at n=31A280187
• G.f. A(x) satisfies -2 = Sum_{n=-oo..+oo} (-1)^n * x^(2*n+1) * (1 + x^n)^(n+1) * A(x)^n.at n=7A382322