This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A386638 #7 Aug 18 2025 18:48:00 %S A386638 0,0,1,1,2,2,4,4,7,7,12,12,19,19,30,30,45,45,67,67,97,97,139,139,195, %T A386638 195,272,272,373,373,508,508,684,684,915,915,1212,1212,1597,1597,2087, %U A386638 2087,2714,2714,3506,3506,4508,4508,5763,5763,7338,7338,9296,9296 %N A386638 Number of integer partitions of n of inseparable type. %C A386638 A multiset is inseparable iff it has no permutation without adjacent equal parts. It is of inseparable type iff any multiset with those multiplicities (type) is inseparable. For example, {1,1,2} is separable but {1,1,1,2} is not; hence (2,1) is of separable type but (3,1) is not. %C A386638 Also the number of integer partitions of n whose greatest part is at least two more than the sum of all the other parts. %F A386638 For n>1, a(n) = A025065(n-2). %F A386638 a(n) = A000041(n) - A336106(n). %e A386638 The a(2) = 1 through a(10) = 12 partitions (A=10): %e A386638 (2) (3) (4) (5) (6) (7) (8) (9) (A) %e A386638 (31) (41) (42) (52) (53) (63) (64) %e A386638 (51) (61) (62) (72) (73) %e A386638 (411) (511) (71) (81) (82) %e A386638 (521) (621) (91) %e A386638 (611) (711) (622) %e A386638 (5111) (6111) (631) %e A386638 (721) %e A386638 (811) %e A386638 (6211) %e A386638 (7111) %e A386638 (61111) %t A386638 Table[Length[Select[IntegerPartitions[n],2*Max@@#>1+n&]],{n,0,15}] %Y A386638 Reduplication of A000070 shifted right. %Y A386638 Same as A025065 shifted right twice. %Y A386638 The Heinz numbers of these partitions are A335126. %Y A386638 Row sums of A386586. %Y A386638 A003242 and A335452 count anti-runs, ranks A333489, patterns A005649. %Y A386638 A239455 counts Look-and-Say partitions, inseparable case A386632. %Y A386638 A325534 counts separable multisets, ranks A335433, sums of A386583. %Y A386638 A325535 counts inseparable multisets, ranks A335448, sums of A386584. %Y A386638 A335434 counts separable factorizations, inseparable A333487. %Y A386638 A336103 counts normal separable multisets, inseparable A336102. %Y A386638 A336106 counts separable type partitions, ranks A335127, sums of A386585. %Y A386638 A386633 counts separable type set partitions, row sums of A386635. %Y A386638 A386634 counts inseparable type set partitions, row sums of A386636. %Y A386638 Cf. A000110, A008284, A047966, A072233, A106351, A124762, A217605, A239964, A279790, A335125, A351293, A386577. %K A386638 nonn,new %O A386638 0,5 %A A386638 _Gus Wiseman_, Aug 14 2025