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 A238524 Numbers n such that the symmetric representation of sigma(n) is formed by two or more parts. 10
 3, 5, 7, 9, 10, 11, 13, 14, 15, 17, 19, 21, 22, 23, 25, 26, 27, 29, 31, 33, 34, 35, 37, 38, 39, 41, 43, 44, 45, 46, 47, 49, 50, 51, 52, 53, 55, 57, 58, 59, 61, 62, 63, 65, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77, 78, 79, 81, 82, 83, 85, 86, 87, 89, 91, 92 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Complement of A238443. First differs from A237046 at a(48). First differs from A237287 at a(55). For more information see A237270. From Hartmut F. W. Hoft, Nov 27 2014: (Start) Suppose n = 2^m * p1^e1 *...* pk^ek where p1 < ... < pk are the odd prime factors of n, m>=0 and all ej>0. Equivalent to the property of numbers in this sequence are: (a) The number of 1's in odd positions equals the number of 1's in even positions in the n-th row of triangle A237048 through an index of the form 2^(m+1)*q where q is an odd divisor of n. (b) There is one odd prime factor pj of n satisfying pj > 2^(m+1) * product_{i=2&] a238524[1, 260] (* data *) (* Hartmut F. W. Hoft, Jul 07 2014 *) (* function for the alternate description of the sequence *) (* functions row[ ] & a237048[ ] are defined in A237048 *) zero249223Q[n_] := Module[{i=2, bound=row[n], width=1}, While[width>=1 && i<=bound, width += (-1)^(i+1) * a237048[n, i]; i++]; width==0] Select[Range[1, 100], zero249223Q] (* data *) (* Hartmut F. W. Hoft, Nov 27 2014 *) CROSSREFS Cf. A196020, A236104, A235791, A237046, A237287, A237591, A237593, A237270, A237271, A238443. Sequence in context: A231564 A325798 A365830 * A237287 A237046 A370421 Adjacent sequences: A238521 A238522 A238523 * A238525 A238526 A238527 KEYWORD nonn AUTHOR Omar E. Pol, Mar 06 2014 STATUS approved

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Last modified June 21 21:50 EDT 2024. Contains 373559 sequences. (Running on oeis4.)