A268497 Records in A268630 (= a(n)^2+a(n+1) is prime).

0, 2, 4, 8, 10, 16, 18, 23, 28, 32, 37, 48, 63, 66, 73, 76, 79, 82, 99, 100, 102, 106, 109, 126, 142, 147, 169, 172, 177, 178, 189, 190, 198, 201, 205, 208, 217, 225, 226, 228, 232, 235, 244, 253, 258, 264, 268, 278, 288, 306, 333, 336, 343, 348, 352, 358, 361, 370, 379, 382

Offset

0,2

Comments

See A268496 for the corresponding indices, A268494-A268495 for "late birds". We use offset 0 here because the first term has a special status (it's not really "late") and also because all related sequences (A268630 and A268494 - A268497) have a(0)=0 and omitting this term yields the corresponding "positive integer" variant.

Links

Table of n, a(n) for n=0..59.

Prog

(PARI) show(n, f="/tmp/b268497.txt", c=0, a=0, u=[a-1])={for(n=1, n, a>=u[#u]&&if(f, write(f, c++-1, " "a), print1(a", ")); u=setunion(u, [a]); while(#u>1&&u[2]==u[1]+1, u=u[^1]); for(k=u[1]+1, 9e9, !setsearch(u, k) && isprime(a*a+k) && (a=k) && break))}

Crossrefs

Sequence in context: A356843 A369492 A339608 * A093886 A352203 A125732

Adjacent sequences: A268494 A268495 A268496 * A268498 A268499 A268500

Keyword

nonn

Author

M. F. Hasler, Feb 09 2016

Status

approved