121121
domain: N
Appears in sequences
- Smallest natural number requiring n words in English (as spoken in England).at n=10A001167
- Rows of Pascal's triangle mod 3.at n=5A006940
- Decimal expansion of a(n) is given by the first n terms of the periodic sequence with initial period 1,2,1.at n=5A037543
- Palindromic numbers which are the difference of two positive cubes.at n=21A038808
- Number of bipartite graphs with 3 edges on nodes {1..n}.at n=14A053526
- Palindromes that are the sum of two shorter palindromes.at n=15A062696
- In the array shown below the n-th row contains all the palindromes that use digits > 0 and have a digit sum of n. The sequence contains the array read by rows.at n=41A082266
- Palindromes in A083114.at n=42A083115
- a(n) = C(n+3,3)*n^3/4.at n=11A085284
- Numbers n such that the set S(n) = {k: k + reverse(k) = n} is not empty, at least one element of S(n) has the same number of digits as n and at least one element of S(n) has one digit less than n has.at n=5A088171
- Smaller of two consecutive numbers with the same prime signature not occurring earlier.at n=20A091405
- a(n) = binomial(n,4) - binomial(floor(n/2),4) - binomial(ceiling(n/2),4).at n=44A111385
- a(n) = n base 5, under morphism f(1) = 121, f(2) = 123, f(3) = 141, f(4) = 142, or 0 if n base 5 has a zero.at n=5A137850
- Palindromes that are the sum of two positive cubes.at n=22A162710
- Composite numbers whose product of digits is 4.at n=38A201016
- Successive generations of the variant of the Kolakoski sequence.at n=3A201642
- Dates after Jan 01 00 in chronological order which are palindromic when they are written in the format DD.MM.YY. The terms are listed as numbers (without the dots). Leading zeros of the terms are suppressed.at n=7A210888
- Dates after Jan 01 00 in chronological order which are palindromic when they are written according to the format MMDDYY (American standard, short). Leading zeros of the terms are suppressed.at n=8A210895
- List of imprimitive words over the alphabet {1,2}.at n=12A213972
- List of subwords of A003842 arranged in lexicographic order.at n=22A213975