A107973 - OEIS

%I #5 Jan 01 2018 19:31:00

%S 461,503,547,593,641,691,743,797,853,911,971,1033,1097,1163,1231,1301,

%T 1373,1447,1523,1601

%N Numbers of the form a^2 + b for a= 21 to 40 and b= 20 to 1 step -1.

%C Complete list of 20 prime numbers also of the form n^2+n+41 for n=20 to 39

%e 21*21+20=461

%e 22*22+19=503

%e 23*23+18=547

%t #[[1]]^2+#[[2]]&/@Thread[{Range[21,40],Range[20,1,-1]}] (* _Harvey P. Dale_, Jan 01 2018 *)

%K fini,full,nonn

%O 1,1

%A _Pierre CAMI_, Jun 12 2005