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Numbers whose sum of prime indices is twice their alternating sum.
7

%I #8 Dec 10 2021 11:14:20

%S 1,12,63,66,112,190,255,325,408,434,468,609,805,832,931,946,1160,1242,

%T 1353,1380,1534,1539,1900,2035,2067,2208,2296,2387,2414,2736,3055,

%U 3108,3154,3330,3417,3509,3913,4185,4340,4503,4646,4650,4664,4864,5185,5684,5863

%N Numbers whose sum of prime indices is twice their alternating sum.

%C A prime index of n is a number m such that prime(m) divides n. The multiset of prime indices of n is row n of A112798.

%C The alternating sum of a sequence (y_1,...,y_k) is Sum_i (-1)^(i-1) y_i.

%C The Heinz number of a partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k), so these are also Heinz numbers of partitions whose sum is twice their alternating sum.

%F A056239(a(n)) = 2*A316524(a(n)).

%F A346697(a(n)) = 3*A346698(a(n)).

%e The terms and their prime indices begin:

%e 1: ()

%e 12: (2,1,1)

%e 63: (4,2,2)

%e 66: (5,2,1)

%e 112: (4,1,1,1,1)

%e 190: (8,3,1)

%e 255: (7,3,2)

%e 325: (6,3,3)

%e 408: (7,2,1,1,1)

%e 434: (11,4,1)

%e 468: (6,2,2,1,1)

%e 609: (10,4,2)

%e 805: (9,4,3)

%e 832: (6,1,1,1,1,1,1)

%e 931: (8,4,4)

%e 946: (14,5,1)

%e 1160: (10,3,1,1,1)

%t primeMS[n_]:=If[n==1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]];

%t ats[y_]:=Sum[(-1)^(i-1)*y[[i]],{i,Length[y]}];

%t Select[Range[1000],Total[primeMS[#]]==2*ats[primeMS[#]]&]

%Y These partitions are counted by A000712 up to 0's.

%Y An ordered version is A348614, negative A349154.

%Y The negative version is A348617.

%Y The reverse version is A349160, counted by A006330 up to 0's.

%Y A025047 counts alternating or wiggly compositions, complement A345192.

%Y A027193 counts partitions with rev-alt sum > 0, ranked by A026424.

%Y A034871, A097805, and A345197 count compositions by alternating sum.

%Y A035363 = partitions with alt sum 0, ranked by A066207, complement A086543.

%Y A056239 adds up prime indices, row sums of A112798, row lengths A001222.

%Y A103919 counts partitions by alternating sum, reverse A344612.

%Y A116406 counts compositions with alternating sum >= 0, ranked by A345913.

%Y A138364 counts compositions with alternating sum 0, ranked by A344619.

%Y A325534 counts separable partitions, ranked by A335433.

%Y A325535 counts inseparable partitions, ranked by A335448.

%Y A344607 counts partitions with rev-alt sum >= 0, ranked by A344609.

%Y A346697 adds up odd-indexed prime indices.

%Y A346698 adds up even-indexed prime indices.

%Y Cf. A000070, A000290, A001700, A028260, A045931, A120452, A195017, A241638, A257991, A257992, A325698, A345958, A349155.

%K nonn

%O 1,2

%A _Gus Wiseman_, Nov 23 2021