A245798 Catalan number analogs for totienomial coefficients (A238453).
1, 1, 2, 4, 12, 36, 120, 360, 960, 3840, 13824, 41472, 152064, 506880, 2280960, 7983360, 29937600, 99792000, 266112000, 1197504000, 4790016000, 19160064000, 73156608000, 219469824000, 1009561190400, 3533464166400, 12563428147200, 54441521971200, 155547205632000
Offset: 0
Keywords
Examples
We see that A238453(10,5) = 72 and A000010(5+1) = 2, so a(5) = (1/2)*72 = 36.
Links
- Tom Edgar, Table of n, a(n) for n = 0..28
- Tom Edgar, Totienomial Coefficients, INTEGERS, 14 (2014), #A62.
- Tom Edgar and Michael Z. Spivey, Multiplicative functions, generalized binomial coefficients, and generalized Catalan numbers, Journal of Integer Sequences, Vol. 19 (2016), Article 16.1.6.
Programs
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Sage
[(1/euler_phi(n+1))*prod(euler_phi(i) for i in [1..2*n])/prod(euler_phi(i) for i in [1..n])^2 for n in [0..100]]
Comments