A098364 - OEIS

%I #17 Nov 11 2021 20:07:53

%S 1,4,4,1,16,1,4,4,4,4,2,16,1,16,2,1,8,4,4,8,1,3,4,2,16,2,4,3,5,12,1,8,

%T 8,1,12,5,6,20,3,4,4,4,3,20,6,2,24,5,12,2,2,12,5,24,2,3,8,6,20,6,1,6,

%U 20,6,8,3,7,12,2,24,10,3,3,10,24,2,12,7,3,28,3,8,12,5,9,5,12,8,3,28,3

%N Multiplication table of the digits of the square root of 2 read by antidiagonals.

%H Michel Marcus, <a href="/A098364/b098364.txt">Antidiagonals n = 1..100, flattened</a>

%F T(n,k) = A003991(A002193(n), A002193(k)). - _Michel Marcus_, Nov 03 2021

%e Triangle begins:

%e   1;

%e   4,4;

%e   1,16,1;

%e   4,4,4,4;

%e   ...

%e Array begins:

%e   1  4 1  4 2 ...

%e   4 16 4 16 8 ...

%e   1  4 1  4 2 ...

%e   4 16 4 16 8 ...

%e   2  8 2  8 4 ...

%e   ...

%o (PARI) sqrt2(nn) = {my(r=0, x=2, list = List(), d); for(digits=1, nn, d=0; while((20*r+d)*d <= x, d++); d--; listput(list, d); x=100*(x-(20*r+d)*d); r=10*r+d;); Vec(list);} \\ A002193

%o lista(nn) = {my(dd = sqrt2(nn)); for (n=1, nn, for (k=1, n, print1(dd[k]*dd[n-k+1], ", ")));} \\ _Michel Marcus_, Nov 11 2021

%Y Cf. A002193, A003991, A098365, A098366, A098367.

%K nonn,tabl,base

%O 1,2

%A Douglas Stones (dssto1(AT)student.monash.edu.au), Sep 04 2004

%E Offset changed to 1 and a(34)=1 inserted by _Georg Fischer_, Nov 02 2021