Could someone compute a few more terms for A006128 ?

Max relf at unn.ac.ru
Tue Nov 8 00:34:03 CET 2005


Thomas Baruchel wrote:

> working on the complexity of some function in a library I am currently
> writing, I would like to have A006128 up to n=48 (or more ;-)
> I have written a piece of code, but it quickly becomes very slow.
> Could someone post on seqfan (and add to the database) a few more terms ?

First 100 terms derived from G.f.:

? sum(n=1,100,n*x^n*prod(k=1,n,1/(1-x^k) + O(x^100)))
%1 = x + 3*x^2 + 6*x^3 + 12*x^4 + 20*x^5 + 35*x^6 + 54*x^7 + 86*x^8 + 128*x^9 + 192*x^10 + 275*x^11 + 399*x^12 + 556*x^13 + 780*x^14 + 1068*x^15 + 1463*x^16 + 1965*x^17 + 2644*x^18 + 3498*x^19 + 4630*x^20 + 6052*x^21 + 7899*x^22 + 10206*x^23 + 13174*x^24 + 16851*x^25 + 21522*x^26 + 27294*x^27 + 34545*x^28 + 43453*x^29 + 54563*x^30 + 68135*x^31 + 84927*x^32 + 105366*x^33 + 130462*x^34 + 160876*x^35 + 198014*x^36 + 242812*x^37 + 297201*x^38 + 362587*x^39 + 441546*x^40 + 536104*x^41 + 649791*x^42 + 785437*x^43 + 947812*x^44 + 1140945*x^45 + 1371173*x^46 + 1644136*x^47 + 1968379*x^48 + 2351597*x^49 + 2805218*x^50 + 3339869*x^51 + 3970648*x^52 + 4712040*x^53 + 5584141*x^54 + 6606438*x^55 + 7805507*x^56 + 9207637*x^57 + 10847703*x^58 + 12760906*x^59 + 14993151*x^60 + 17591088*x^61 + 20614860*x^62 + 24126393*x^63 + 28203987*x^64 + 32929312*x^65 + 38404426*x^66 + 44736332*x^67 + 52057537*x^68 + 60508103*x^69 + 70259278*x^70 + 81493581*x^71 + 94432246*x^72 + 109311863*x^73 + 126417307
*x^74 + 146054892*x^75 + 
168590041*x^76 + 194417783*x^77 + 224006431*x^78 + 257863391*x^79 + 296587112*x^80 + 340828172*x^81 + 391348925*x^82 + 448980978*x^83 + 514694110*x^84 + 589547701*x^85 + 674772306*x^86 + 771715076*x^87 + 881933249*x^88 + 1007135164*x^89 + 1149288434*x^90 + 1310553403*x^91 + 1493410529*x^92 + 1700586677*x^93 + 1935201437*x^94 + 2200688624*x^95 + 2500965274*x^96 + 2840344772*x^97 + 3223735387*x^98 + 3656545760*x^99 + 4144913179*x^100 + O(x^101)

Max





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