cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A065024 Number of n-digit biquanimous numbers in base 10 allowing leading zeros.

Original entry on oeis.org

1, 10, 136, 2056, 29246, 376414, 4366881, 47111408, 487875964, 4951921240, 49815780829, 499304300676, 4997363405880, 49989815235610, 499959437775564, 4999832460244272, 49999282163551040, 499996822399017380, 4999985554326500949, 49999932964605448756, 499999684083134646700, 4999998493912339729030, 49999992756990963293576, 499999964931001199898296, 4999999829289953917354596
Offset: 1

Views

Author

N. J. A. Sloane, Nov 03 2001

Keywords

Comments

A biquanimous number (A064544) is a number whose digits can be split into two groups with equal sums.

References

Crossrefs

Column k=9 of A288638.

Formula

G.f.: (2764800*x^35 -54743040*x^34 +535723776*x^33 -3484062592*x^32 +17047244288*x^31 -67056352000*x^30 +220043616032*x^29 -610136398384*x^28 +1428398369904*x^27 -2800237309450*x^26 +4555415187081*x^25 -6116515610358*x^24 +6790044899737*x^23 -6333177380214*x^22 +5196278284089*x^21 -4097957831766*x^20 +3395084470412*x^19 -2936902021347*x^18 +2431358755383*x^17 -1791957130479*x^16 +1141680065910*x^15 -626654334304*x^14 +298277671441*x^13 -124021600362*x^12 +45181016933*x^11 -14371192060*x^10 +3953830871*x^9 -928344574*x^8 +183129613*x^7 -29820446*x^6 +3925130*x^5 -406196*x^4 +31739*x^3 -1755*x^2 +61*x-1) / ((10*x-1) *(5*x-1) *(4*x-1)^2 *(3*x-1)^3 *(2*x-1)^8 *(x-1)^14). - Alois P. Heinz, Jun 12 2017
Limit_{n->oo} a(n)/10^n = 1/2. - Stefano Spezia, Sep 09 2023

A288550 Number of strings of n digits from 1...9 such that a signed summation of the digits exists making the sum = 0.

Original entry on oeis.org

1, 0, 9, 108, 1569, 20230, 229203, 2278745, 21214753, 192899244, 1741242069, 15684465423, 141196229849, 1270871708340, 11438182427193, 102944790695746, 926507214592705, 8338579980466304, 75047276148618205, 675425698975426255, 6078832109331582297
Offset: 0

Views

Author

Hugo Pfoertner, Jun 11 2017

Keywords

Examples

			a(2)=9, because 11, 22, ..., 99 can be written as 1-1=0, 2-2=0, ...
		

Crossrefs

Formula

Limit_{n->oo} a(n)/9^n = 1/2.
G.f.: (4447872*x^35 +731808*x^34 -31561200*x^33 -9438744*x^32 +95630316*x^31 +43022340*x^30 -156898794*x^29 -98774388*x^28 +140941738*x^27 +120112934*x^26 -46571519*x^25 -49352408*x^24 -50794519*x^23 -70733352*x^22 +118351595*x^21 +120154070*x^20 -162641593*x^19 -54549200*x^18 +156403902*x^17 -38131997*x^16 -93427552*x^15 +56672934*x^14 +28535743*x^13 -26850890*x^12 -1996107*x^11 +5000082*x^10 -264871*x^9 -434046*x^8 +41593*x^7 +13610*x^6 +4622*x^5 -4524*x^4 +1500*x^3 -276*x^2 +26*x -1) / ((9*x-1) *(4*x-1) *(3*x-1)^2 *(2*x-1)^3 *(x+1)^7 *(x-1)^8). - Alois P. Heinz, Jun 11 2017
a(n) = (9^n - A065025(n))/2 for n>0. - Alois P. Heinz, Jun 12 2017

Extensions

a(11)-a(20) from Alois P. Heinz, Jun 11 2017
Showing 1-2 of 2 results.