cp's OEIS Frontend

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.

A328163 Number of integer partitions of n whose unsigned differences have a different GCD than the GCD of their parts all minus 1.

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%I A328163 #7 Oct 09 2019 10:02:41
%S A328163 0,0,1,1,2,1,4,2,5,5,9,5,15,9,19,16,28,16,44,21,55,38,73,34,109,46,
%T A328163 130,73,170,66,251,78,287,137,364,119,522,135,590,236,759,190,1042,
%U A328163 219,1175,425,1460,306,2006,347,2277,671,2780,471,3734,584,4197,1087
%N A328163 Number of integer partitions of n whose unsigned differences have a different GCD than the GCD of their parts all minus 1.
%C A328163 Zeros are ignored when computing GCD, and the empty set has GCD 0.
%e A328163 The a(2) = 1 through a(12) = 15 partitions (A = 10, B = 11, C = 12):
%e A328163   (2)  (3)  (4)   (5)  (6)    (7)   (8)     (9)    (A)      (B)     (C)
%e A328163             (22)       (33)   (52)  (44)    (63)   (55)     (83)    (66)
%e A328163                        (42)         (62)    (72)   (64)     (92)    (84)
%e A328163                        (222)        (422)   (333)  (73)     (722)   (93)
%e A328163                                     (2222)  (522)  (82)     (5222)  (A2)
%e A328163                                                    (442)            (444)
%e A328163                                                    (622)            (552)
%e A328163                                                    (4222)           (633)
%e A328163                                                    (22222)          (642)
%e A328163                                                                     (822)
%e A328163                                                                     (3333)
%e A328163                                                                     (4422)
%e A328163                                                                     (6222)
%e A328163                                                                     (42222)
%e A328163                                                                     (222222)
%t A328163 Table[Length[Select[IntegerPartitions[n],GCD@@Differences[#]!=GCD@@(#-1)&]],{n,0,30}]
%Y A328163 The complement to these partitions is counted by A328164.
%Y A328163 The GCD of the divisors of n all minus 1 is A258409(n).
%Y A328163 The GCD of the prime indices of n all minus 1 is A328167(n).
%Y A328163 Partitions whose parts minus 1 are relatively prime are A328170.
%Y A328163 Cf. A000837, A018783, A175342, A279945, A289508, A328168, A328169.
%K A328163 nonn
%O A328163 0,5
%A A328163 _Gus Wiseman_, Oct 07 2019