cp's OEIS Frontend

A278168 a(n) = number of integers one less than a prime encountered before reaching 0 when starting from k = ((n+1)^2)-1 and iterating map k -> k - A002828(k).

%I A278168 #6 Nov 14 2016 10:38:20
%S A278168 0,1,1,3,4,5,5,8,10,13,15,16,17,19,20,23,25,28,29,31,35,39,40,42,45,
%T A278168 47,49,52,56,59,62,66,69,73,76,78,82,87,92,96,100,103,107,112,116,120,
%U A278168 123,127,133,137,143,151,155,159,162,167,174,177,184,186,192,198,202,209,216,220,225,232,236,244,250,254,258,261,267,278,282,287,292,301
%N A278168 a(n) = number of integers one less than a prime encountered before reaching 0 when starting from k = ((n+1)^2)-1 and iterating map k -> k - A002828(k).
%H A278168 Antti Karttunen, <a href="/A278168/b278168.txt">Table of n, a(n) for n = 1..10000</a>
%F A278168 a(1) = A277488(1); for n > 1, a(n) = A277488(n) + a(n-1).
%e A278168 For n=4, starting from k = ((4+1)^2)-1, and iterating k -> A255131(k), yields 24 -> 21 -> 18 -> 16 -> 15 -> 11 -> 8 -> 6 -> 3 before 0 is reached. Subtracting one from each gives [25, 22, 19, 17, 16, 12, 9, 7, 4], of which only 19, 17, and 7 are primes, thus a(4) = 3.
%o A278168 (Scheme) (definec (A278168 n) (if (= 1 n) (A277488 n) (+ (A277488 n) (A278168 (- n 1)))))
%Y A278168 Partial sums of A277488.
%Y A278168 Cf. A002828, A255131, A278166, A278167.
%K A278168 nonn
%O A278168 1,4
%A A278168 _Antti Karttunen_, Nov 13 2016