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 A191639 a(n) = floor((1 + 4^n)/(1 + 3*n)). 2
 1, 2, 6, 19, 64, 215, 744, 2621, 9362, 33825, 123361, 453438, 1677721, 6242685, 23342213, 87652393, 330382099, 1249445031, 4739274257, 18024780783, 68719476736, 262569940961, 1005267773966, 3855821598776, 14814472458455, 57007590219879, 219687786700999 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..1000 MATHEMATICA f[n_] := Floor[(1+4^n)/(1+3 n)] Table[f[n], {n, 1, 40}]     (* A191639 *) PROG (MAGMA) [Floor((1+4^n)/(1+3*n)): n in [1..30] ]; // Vincenzo Librandi, Sep 10 2011 (Maxima) A191639(n):=floor((1+4^n)/(1+3*n))\$ makelist(A191639(n), n, 1, 30); /* Martin Ettl, Oct 25 2012 */ CROSSREFS Cf. A191638. Sequence in context: A148467 A148468 A148469 * A329802 A151283 A176950 Adjacent sequences:  A191636 A191637 A191638 * A191640 A191641 A191642 KEYWORD nonn AUTHOR Clark Kimberling, Jun 09 2011 STATUS approved

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Last modified February 26 05:19 EST 2020. Contains 332276 sequences. (Running on oeis4.)