77421

Appears in sequences

• Strong pseudoprimes to base 61.at n=20A020287
• Terms of A073872 that do not change their position in the rearrangement; i.e., values of A073872(n) which equal n(n+1)/2.at n=32A073873
• Molien series for 16-dimensional group of structure 2^4.O_{4}^{+}(F_2) = 2^4.(S_3 X S_3).2 and order 1152, corresponding to genus 2 complete weight enumerators of Hermitian self-dual GF(2)-linear codes over GF(4) containing the all-ones vector.at n=14A092203
• Triangular numbers T such that T+10 is the next prime after T.at n=13A129540
• Greatest number m such that the fractional part of (4/3)^A154133(n) >= 1-(1/m).at n=9A154137
• Triangular numbers composed of only digits with line segments or both line segments and curves {1, 2, 4, 5, 7}.at n=23A247021
• a(n) is the least integer m such that A001006(m) is divisible by prime(n)^2 or -1 if no such m exists.at n=33A354293
• Hexagonal numbers that are sphenic numbers.at n=38A380007