A372560 - OEIS

%I #4 May 10 2024 11:00:12

%S 27,165,41,8021,501,31,12408149,48469,189,47,19607957362005,299193685,

%T 4565,285,71,32439509492992549521282389,7552911875069269,1758549,6869,

%U 429,107,58947232705679751034215288252890081792789279233365,3195535888075328282939605996885,173230347605,2643285,10325,645,161

%N Array read by upward antidiagonals: A(n, k) = A371094(A(n-1, k)) for n > 1, k >= 1; A(1, k) = A372443(k-1).

%e Array begins:

%e n\k|        1          2        3        4        5         6           7

%e ---+-----------------------------------------------------------------------

%e 1  |       27,        41,      31,      47,      71,      107,        161,

%e 2  |      165,       501,     189,     285,     429,      645,       1941,

%e 3  |     8021,     48469,    4565,    6869,   10325,    31061,     374101,

%e 4  | 12408149, 299193685, 1758549, 2643285, 7951701, 95769941, 9216283989,

%o (PARI)

%o up_to = 28;

%o A000265(n) = (n>>valuation(n,2));

%o A372443(n) = { my(x=27); while(n, x=A000265(3*x+1); n--); (x); };

%o A371094(n) = { my(m=1+3*n, e=valuation(m,2)); ((m*(2^e)) + (((4^e)-1)/3)); };

%o A372560sq(n,k) = if(1==n,A372443(k-1),A371094(A372560sq(n-1,k)));

%o A372560list(up_to) = { my(v = vector(up_to), i=0); for(a=1,oo, for(col=1,a, i++; if(i > up_to, return(v)); v[i] = A372560sq((a-(col-1)),col))); (v); };

%o v372560 = A372560list(up_to);

%o A372560(n) = v372560[n];

%Y Cf. A371094, A372282, A372443 (the top row), A372444 (the leftmost column), A372561.

%K nonn,tabl

%O 1,1

%A _Antti Karttunen_, May 08 2024