100980

Appears in sequences

• Infinitary sociable numbers (smallest member of cycle).at n=6A004607
• Values of m such that N = (am+1)(bm+1)(cm+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,69.at n=11A065702
• Numbers n divisible by exactly four nontrivial permutations (rearrangements) of the digits of n.at n=5A090059
• Number of preferential arrangements of n labeled elements where the exchange of elements among the levels is restricted to levels of different occupation numbers.at n=9A122404
• Amicable triples: numbers such that sigma(x) = sigma(y) = sigma(z) = x+y+z, x<y<z. We order these triples according to the common value of sigma. Sequence gives x numbers.at n=23A125490
• Amicable triples: numbers such that sigma(x) = sigma(y) = sigma(z) = x+y+z, x<y<z. We order these triples according to the common value of sigma. Sequence gives x numbers.at n=24A125490
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, 0, 0), (-1, 0, 1), (0, 1, 0), (1, -1, 1), (1, 1, -1)}.at n=10A148484
• Numbers n such that product of double factorials of the digits of n equals sigma(n).at n=22A158989
• Numbers with prime factorization p*q*r*s^2*t^3 (where p, q, r, s, t are distinct primes).at n=31A190111
• Number of (n+2)X(n+2) symmetric binary matrices without the pattern 0 1 1 diagonally or antidiagonally.at n=3A190536
• Integers n such that n^2 = 2*x*(y-x), where x and y are consecutive terms in A014574.at n=37A255230
• a(1) = 1; a(n > 1) = Sum_{0 < k < n} (-1)^(n - k - 1) a(n - k) Sum_{d|k} a(d).at n=32A317853
• Smallest member of bi-unitary sociable quadruples.at n=7A319915
• First elements of maximal isospectral chains of length 3.at n=14A335082
• a(n) is the smallest number m with exactly n divisors whose first digit equals the first digit of m.at n=30A357300
• Smallest members of infinitary sociable quadruples.at n=5A361811