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A276375
Numbers n such that A240024(n + 1) = A002808(n).
2
1, 2, 3, 11, 22, 29, 47, 49, 52, 67, 78, 79, 80, 91, 103, 104, 109, 111, 121, 130, 137, 148, 152, 159, 179, 184, 190, 200, 207, 215, 222, 241, 264, 278, 291, 307, 309, 316, 331, 336, 343, 347, 350, 361, 373, 380, 400, 409, 415, 430, 435, 445, 450, 453, 468
OFFSET
1,2
MATHEMATICA
c = Select[Range@ 600, CompositeQ]; a = {1, 4}; Do[k = 6; While[Or[PrimeQ@ k, MemberQ[a, k], CoprimeQ[a[[i - 1]], k]], k++]; AppendTo[a, k], {i, 3, Length@c + 1}]; Flatten@ Position[Union /@ Transpose@ {Rest@ a, c}, w_ /; Length@ w == 1] (* Michael De Vlieger, Sep 01 2016 *)
PROG
(Haskell)
a276375 n = a276375_list !! (n - 1)
a276375_list = filter (\i -> a240024 (i + 1) == a002808 i) [1..]
CROSSREFS
KEYWORD
nonn
AUTHOR
Peter Kagey, Aug 31 2016
STATUS
approved