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A304488 Numbers k where A304356(k)-A304358(k) changes sign. 1
17, 18, 19, 23, 24, 223, 224, 261, 263, 264, 385, 415, 417, 418, 442, 812, 815, 822, 823, 824, 826, 843, 846, 849, 850, 851, 875, 3877, 3879, 3887, 3907, 3968, 3971, 3973, 3975, 4247, 4249, 4269, 4270, 4327, 4394, 4399, 4802, 4804, 4806, 4809, 4810, 4812, 5072, 5078, 5087, 5088, 5095, 5426, 5427, 5483 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
EXAMPLE
A304356(n)>A304358(n) for n=1..16, but A304356(17)=1039<A304358(17)=1129, so a(1)=17.
MAPLE
N:= 10^5:
P1:= select(isprime, [seq(i, i=1..N, 4)]):
P3:= select(isprime, [seq(i, i=3..N, 4)]):
A1:= select(isprime, P1[1..-3]+P1[2..-2]+P1[3..-1]):
A3:= select(isprime, P3[1..-3]+P3[2..-2]+P3[3..-1]):
M:= min(nops(A1), nops(A3)):
sg:= [seq(signum(A1[i]-A3[i]), i=1..M)]:
select(t -> sg[t]<>sg[t-1], [$2..M]);
CROSSREFS
Sequence in context: A296757 A297287 A018822 * A043594 A043825 A043831
KEYWORD
nonn,look
AUTHOR
J. M. Bergot and Robert Israel, May 13 2018
STATUS
approved

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Last modified March 28 16:12 EDT 2024. Contains 371254 sequences. (Running on oeis4.)