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 A301764 Number of ways to choose a constant rooted partition of each part in a constant rooted partition of n such that the flattened sequence is also constant. 4
 1, 1, 2, 3, 4, 4, 6, 5, 6, 7, 8, 5, 10, 7, 8, 10, 10, 6, 12, 7, 12, 13, 10, 5, 14, 12, 11, 11, 14, 7, 18, 9, 12, 13, 11, 12, 20, 10, 10, 13, 18, 9, 20, 9, 14, 20, 12, 5, 20, 15, 19, 14, 17, 7, 18, 16, 20, 17, 12, 5, 26, 13, 12, 21, 18, 17, 24, 9, 15, 13, 22, 9 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS A rooted partition of n is an integer partition of n - 1. LINKS Andrew Howroyd, Table of n, a(n) for n = 1..1000 EXAMPLE The a(11) = 8 rooted twice-partitions: (9), (333), (111111111), (4)(4), (22)(22), (1111)(1111), (1)(1)(1)(1)(1), ()()()()()()()()()(). MATHEMATICA Table[If[n===1, 1, DivisorSum[n-1, If[#===1, 1, DivisorSigma[0, #-1]]&]], {n, 100}] PROG (PARI) a(n)=if(n==1, 1, sumdiv(n-1, d, if(d==1, 1, numdiv(d-1)))) \\ Andrew Howroyd, Aug 26 2018 CROSSREFS Cf. A002865, A007425, A063834, A093637, A127524, A295931, A300383, A301422, A301462, A301467, A301480, A301706. Sequence in context: A298933 A091860 A333995 * A181833 A202650 A228286 Adjacent sequences:  A301761 A301762 A301763 * A301765 A301766 A301767 KEYWORD nonn AUTHOR Gus Wiseman, Mar 26 2018 STATUS approved

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Last modified January 18 11:48 EST 2021. Contains 340254 sequences. (Running on oeis4.)