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 A066186 Sum of all parts of all partitions of n. 117
 0, 1, 4, 9, 20, 35, 66, 105, 176, 270, 420, 616, 924, 1313, 1890, 2640, 3696, 5049, 6930, 9310, 12540, 16632, 22044, 28865, 37800, 48950, 63336, 81270, 104104, 132385, 168120, 212102, 267168, 334719, 418540, 520905, 647172, 800569, 988570, 1216215, 1493520 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS Sum of the zeroth moments of all partitions of n. Also the number of one-element transitions from the integer partitions of n to the partitions of n-1 for labeled parts with the assumption that any part z is composed of labeled elements of amount 1, i.e., z = 1_1 + 1_2 +... + 1_z. Then one can take from z a single element in z different ways. E.g., for n=3 to n=2 we have A066186(3) = 9 and [111] --> [11], [111] --> [11], [111] --> [11], [12] --> [111], [12] --> [111], [12] --> [2], [3] --> 2, [3] --> 2, [3] --> 2. For the unlabeled case, one can take a single element from z in only one way. Then the number of one-element transitions from the integer partitions of n to the partitions of n-1 is given by A000070. E.g., A000070(3) = 4 and for the transition from n=3 to n=2 one has [111] --> [11], [12] --> [11], [12] --> [2], [3] --> [2]. - Thomas Wieder, May 20 2004 Row sums of triangle A138785 and of triangle A181187. - Omar E. Pol, Feb 26 2012 Also sum of all parts of all regions of n (Cf. A206437). - Omar E. Pol, Jan 13 2013 Row sums of triangle A221529. - Omar E. Pol, Jan 21 2013 First differences give A138879. - Omar E. Pol, Aug 16 2013 LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..1000 F. G. Garvan, Higher-order spt functions, Adv. Math. 228 (2011), no. 1, 241-265, alternate copy. - From N. J. A. Sloane, Jan 02 2013 F. G. Garvan, Higher-order spt functions, arXiv:1008.1207 [math.NT], 2010. FORMULA a(n) = n * A000041(n). - Omar E. Pol, Oct 10 2011 G.f. = x*d/dx [prod_{k>0} 1/(1-x^k)], i.e., derivative of g.f. for A000041. - Jon Perry, Mar 17 2004 (adjusted to match the offset by Geoffrey Critzer, Nov 29 2014) Equals A132825 * [1, 2, 3,...]. - Gary W. Adamson, Sep 02 2007 a(n) = A066967(n) + A066966(n). - Omar E. Pol, Mar 10 2012 a(n) = A207381(n) + A207382(n). - Omar E. Pol, Mar 13 2012 a(n) = A006128(n) + A196087(n). - Omar E. Pol, Apr 22 2012 a(n) = A220909(n)/2. - Omar E. Pol, Jan 13 2013 a(n) = Sum_{k=1..n} A000203(k)*A000041(n-k), n >= 1. - Omar E. Pol, Jan 20 2013 a(n) = Sum_{k=1..n} k*A036043(n,n-k+1). - L. Edson Jeffery, Aug 03 2013 a(n) = Sum_{k=1..n} A024916(k)*A002865(n-k), n >= 1. - Omar E. Pol, Jul 13 2014 a(n) ~ exp(Pi*sqrt(2*n/3))/(4*sqrt(3)) * (1 - (sqrt(3/2)/Pi + Pi/(24*sqrt(6))) / sqrt(n)). - Vaclav Kotesovec, Oct 24 2016 EXAMPLE a(3)=9 because the partitions of 3 are: 3, 2+1 and 1+1+1; and (3) + (2+1) + (1+1+1) = 9. a(4)=20 because A000041(4)=5 and 4*5=20. MAPLE with(combinat): a:= n-> n*numbpart(n): seq(a(n), n=0..50); # Zerinvary Lajos, Apr 25 2007 MATHEMATICA PartitionsP[ Range[0, 60] ] * Range[0, 60] PROG (PARI) a(n)=numbpart(n)*n \\ Charles R Greathouse IV, Mar 10 2012 (Haskell) a066186 = sum . concat . ps 1 where    ps _ 0 = [[]]    ps i j = [t:ts | t <- [i..j], ts <- ps t (j - t)] -- Reinhard Zumkeller, Jul 13 2013 (Sage) [n*Partitions(n).cardinality() for n in range(41)] # Peter Luschny, Jul 29 2014 CROSSREFS Cf. A000041, A093694, A000070, A132825, A001787 (same for ordered partitions), A277029. Sequence in context: A241944 A256054 A164931 * A059403 A009909 A009910 Adjacent sequences:  A066183 A066184 A066185 * A066187 A066188 A066189 KEYWORD easy,nonn,nice AUTHOR Wouter Meeussen, Dec 15 2001 EXTENSIONS a(0) added by Franklin T. Adams-Watters, Jul 28 2014 STATUS approved

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Last modified March 20 08:01 EDT 2018. Contains 300961 sequences. (Running on oeis4.)