31121

Properties

Appears in sequences

• Primes that are palindromic in base 5.at n=38A029973
• Start with the prime 11; next prime must exceed previous prime, contain no 0's and start with last digit of previous prime.at n=8A053649
• Primes whose product of digits is 6.at n=16A107692
• Number of degree-n permutations such that number of cycles of size 2k-1 is odd (or zero) for every k.at n=8A130278
• Floor of sum of the first n^2 square roots.at n=36A138357
• 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), (0, -1, 0), (0, 0, 1), (0, 1, -1), (1, 0, 1)}.at n=8A150462
• a(1) = 3. For n > 1, Ulam's spiral is started with a(n-1), and the primes p on the NE spoke are considered. a(n) is the minimal p that is the lesser of a twin prime pair.at n=32A163586
• a(0)=113, then a(n) = smallest prime p not already used such that the first three digits of p = the last three digits of a(n-1).at n=8A175687
• Incorrect duplicate of A062343.at n=34A176254
• Primes p such that reversal(p) - 13 is a square.at n=30A176371
• Primes of the form x^3 + y^3 - 1, where x and y are primes.at n=8A217718
• Numbers that eventually reach 1 under "x -> sum of 4th power of digits of x".at n=22A219111
• Primes of the form 2*n^2+86*n+41.at n=35A243958
• Indices of the start of 10 successive distinct digits in the decimal expansion of Pi.at n=16A258157
• Unique representation of nonnegative numbers by iterated tribonacci A, B and C sequences.at n=27A316713
• a(n) is the start of the first maximal string of n consecutive primes such that the sum of squares of pairs of consecutive primes in the string is always divisible by 10.at n=15A346215
• a(n) is the row of the Trithoff (tribonacci) array that contains the tails of the sequence which is n times the tribonacci numbers.at n=39A351685
• Number of edge covers in the n-book graph.at n=5A356198
• Emirps p such that p == 1 (mod s) and R(p) == 1 (mod s), where R(p) is the digit reversal of p and s the sum of digits of p.at n=23A356947
• Prime numbersat n=3351