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A127232
Eulerian numbers A000295 appearing in the intersection of Fibonacci and Lucas sequences A124168 and A127208.
2
1, 120, 524268, 140737488355280, 2596148429267413814265248164609936, 57896044618658097711785492504343953926634992332820282019728792003956564819712
OFFSET
1,2
COMMENTS
a(n) is common to the r-step Fibonacci sequence and the s-step Lucas sequence for s=A001792(n)-2 and r=s-n+1. See A127208 for more information about the intersection of Fibonacci and Lucas sequences.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..8 (shortened by N. J. A. Sloane, Jan 13 2019)
FORMULA
a(n) = 2^(k-1)-k for k=A001792(n).
EXAMPLE
a(2)=120 appears in the 5-step Fibonacci sequence A001591 and the 6-step Lucas sequence A074584. a(3)=524268 appears in the 16-step Fibonacci sequence and the 18-step Lucas sequence.
PROG
(Magma) [2^((n+2)*2^(n-1)-1)-(n+2)*2^(n-1): n in [1..7]]; // Vincenzo Librandi, Aug 26 2011
(PARI) a(n) = my(k=(n+2)*2^(n-1)); 2^(k-1)-k; \\ Michel Marcus, Mar 25 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
T. D. Noe, Jan 09 2007
STATUS
approved