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 A307322 Irregular triangle where row n is a list of indices in A002110 with multiplicity whose product is A004394(n). 1
 0, 1, 1, 1, 2, 1, 2, 1, 1, 2, 2, 2, 1, 1, 1, 2, 1, 3, 1, 1, 3, 2, 3, 1, 1, 1, 3, 1, 2, 3, 1, 1, 2, 3, 1, 1, 4, 2, 4, 1, 1, 1, 4, 1, 2, 4, 1, 1, 2, 4, 1, 1, 1, 2, 4, 1, 2, 2, 4, 1, 1, 3, 4, 1, 2, 5, 1, 1, 2, 5, 1, 1, 1, 2, 5, 1, 2, 2, 5, 1, 1, 3, 5, 1, 1, 2, 2 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 COMMENTS Analogous to A306737. The first 52 terms of a(n) and A306737 are identical, since the first 19 terms of A002182 and A004394 are the same, and the first two terms of row 20 are the same. a(20) = 4,2,1,1,1, while A306737(20) = 4,2,2. Each superabundant number A004394(n) can be expressed as a product of primorials in A002110. Row 1 = {0} by convention. Maximum value in row n = A001221(A004394(n)). Row n in reverse order is the conjugate of the list of the multiplicities of the prime divisors of A004394(n). LINKS Michael De Vlieger, Table of n, a(n) for n = 1..10664 (rows 1 <= n <= 1200, flattened). Michael De Vlieger, Relation between A307322 and A306737. EXAMPLE Terms in the first rows n of this sequence, followed by the corresponding primorials whose product = A004394(n): n T(n,k) A002110(T(n,k)) A004394(n) ----------------------------------------------- 1: 0; 1 = 1 2: 1; 2 = 2 3: 1, 1; 2 * 2 = 4 4: 2; 6 = 6 5: 1, 2; 2 * 6 = 12 6: 1, 1, 2; 2 * 2 * 6 = 24 7: 2, 2; 6 * 6 = 36 8: 1, 1, 1, 2; 2 * 2 * 2 * 6 = 48 9: 1, 3; 2 * 30 = 60 10: 1, 1, 3; 2 * 2 * 30 = 120 11: 2, 3; 6 * 30 = 180 12: 1, 1, 1, 3; 2 * 2 * 2 * 30 = 240 13: 1, 2, 3; 2 * 6 * 30 = 360 14: 1, 1, 2, 3; 2 * 2 * 6 * 30 = 720 15: 1, 1, 4; 2 * 2 * 210 = 840 ... Row 6 = {1,1,2} since A002110(1)*A002110(1)*A002110(2) = 2*2*6 = 24 and A004394(6) = 24. The conjugate of {1,1,2} = {3,1} and 24 = 2^3 * 3^1. Row 10 = {1,1,3} since A002110(1)*A002110(1)*A002110(3) = 2*2*30 = 120 and A004394(10) = 120. The conjugate of {1,1,3} = {3,1,1} and 120 = 2^3 * 3^1 * 5^1. MATHEMATICA Block[{s = Array[DivisorSigma[1, #]/# &, 10^6]}, Map[Table[LengthWhile[#, # >= i &], {i, Max@ #}] &@ If[# == 1, {0}, Function[f, ReplacePart[Table[0, {PrimePi[f[[-1, 1]]]}], #] &@ Map[PrimePi@ First@ # -> Last@ # &, f]]@ FactorInteger@ #] &@ FirstPosition[s, #][[1]] &, Union@ FoldList[Max, s]] /. {} -> {0}] // Flatten CROSSREFS Cf. A001221, A002110, A002182, A004394, A306737. Sequence in context: A366075 A065373 A047895 * A306737 A178474 A374439 Adjacent sequences: A307319 A307320 A307321 * A307323 A307324 A307325 KEYWORD nonn,tabf AUTHOR Michael De Vlieger, Apr 02 2019 STATUS approved

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Last modified September 12 14:39 EDT 2024. Contains 375851 sequences. (Running on oeis4.)