A098831 a(n) = A069837(n) - (10^n-1)*2/9.

0, 1, 1, 15, 51, 101, 51, 1, 5, 155, 1, 1051, 51, 105, 5, 311, 1335, 355, 105, 31, 55, 51, 105, 1031, 15, 105, 55, 5, 355, 115, 1001, 3115, 35, 551, 331, 1, 305, 51, 3305, 555, 1111, 305, 135, 1131, 1135, 1505, 51, 31, 10355, 5001, 1001, 1335, 1101, 331, 305

Offset

1,4

Comments

This is a way to compress A069837.

Links

Table of n, a(n) for n=1..55.

Prog

(PARI) foo(n) = local(m); if (n < 4, m = q[n + 1], m = q[n%4 + 1] + 10*foo(n\4)); m;
print1(0, ", "); q = [0, 1, 3, 5]; for (n = 2, 70, x = (10^n - 1)*2/9; i = 1; found = 0; while (!found, m = foo(i); if (isprime(x + m), found = 1; print1(m, ", "), i += 2)));

Crossrefs

Cf. A069837.

Sequence in context: A044498 A138082 A002602 * A265039 A039405 A043228

Adjacent sequences: A098828 A098829 A098830 * A098832 A098833 A098834

Keyword

base,easy,nonn,less

Author

David Wasserman, Nov 02 2004

Status

approved