A302188 Number of 3D walks of type bce.
1, 3, 12, 53, 252, 1252, 6416, 33609, 178996, 965660, 5263728, 28936404, 160204336, 892313424, 4995832640, 28096475977, 158638993476, 898844200524, 5108695394096, 29117034808980, 166370716319088, 952789631705104, 5467881256289856, 31438798094242244, 181079794531199440, 1044651995141484912
Offset: 0
Links
- Nachum Dershowitz, Touchard's Drunkard, Journal of Integer Sequences, Vol. 20 (2017), #17.1.5.
Crossrefs
Programs
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Python
from math import comb as binomial def a(n): return sum(binomial(n, k)*sum(binomial(k, j)*binomial(j, j//2)**2 for j in range(k+1)) for k in range(n+1)) print([a(n) for n in range(26)]) # Mélika Tebni, Nov 28 2024
Extensions
a(12)-a(25) from Mélika Tebni, Nov 28 2024
Comments