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A324791
Value of A076042 at its n-th low point.
4
0, 5, 7, 4, 19, 104, 74, 193, 515, 725, 241, 1948, 2948, 709, 8746, 16451, 48443, 47915, 61369, 41566, 136585, 710582, 476516, 1363747, 3165833, 5491067, 11906702, 15854273, 6895924, 38766838, 63676139, 3935833, 209116033, 219826349, 265573243, 263220940
OFFSET
0,2
LINKS
N. J. A. Sloane, Table of n, a(n) for n = 0..4000 (Terms through a(42) from Giovanni Resta)
MAPLE
# Maple program from N. J. A. Sloane, Oct 03 2019; guessb = A325056, guessc = A324791 (this sequence).
Digits := 64;
f := proc(k, M) local j1, twoL, RL, kprime, Mprime;
j1 := 3*k^2+7*k+17/4+2*M;
if issqr(j1) then lprint("Beware, perfect square: k, M, j1 are ", k, M, j1); fi;
twoL := -k-3/2+evalf(sqrt(j1)) ;
RL := floor(twoL/2);
Mprime := M+(k+1)^2 - (2*k*RL+3*RL+2*RL^2);
kprime := 1+k+2*RL;
[twol, RL, Mprime, kprime];
end;
guessb:=[0, 5]; b:=5; guessc:=[0, 5]; c:=5;
for i from 1 to 100 do
t1:=f(b, c);
b:=t1[4]; c:=t1[3]; guessb:=[op(guessb), b]; guessc:=[op(guessc), c];
od:
guessb; guessc;
MATHEMATICA
a=b=c=d=n=0; L={0}; While[Length[L] < 22, n++; a=b; b=c; c=d; d=c + If[c < n^2, n^2, -n^2]; If[a > b < c < d, AppendTo[L, b]]]; L (* Giovanni Resta, Oct 01 2019 *)
PROG
(PARI) \\ See Tomas Rokicki's PARI program in A076042.
CROSSREFS
If we use primes instead of squares we get A008348, A309226, A324782, A324783.
Sequence in context: A096458 A123489 A002338 * A226021 A242059 A178668
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Sep 04 2019
EXTENSIONS
More terms from Giovanni Resta, Oct 01 2019
STATUS
approved