A176252 Smallest primes in growing order where the parts of compositions of integer 7 used as decimal digits enable primes.

7, 43, 61, 151, 223, 241, 313, 331, 421, 1033, 1123, 1213, 1231, 1321, 2113, 2131, 2221, 2311, 3121, 4111, 5011, 10141, 11113, 11131, 11311, 12211, 14011, 21121, 21211, 22111, 30211, 101221, 102121, 111121, 111211, 112111, 131011, 310111

Offset

1,1

Comments

See comments and references of A176251.

15 partitions of integer 7: 7, 1+6, 2+5, 3+4, 1+1+5, 1+2+4, 1+3+3, 2+2+3, 1+1+1+4, 1+1+2+3, 1+2+2+2, 1+1+1+1+3, 1+1+1+2+2, 1+1+1+1+1+2, 1+1+1+1+1+1+1

partition 2+5 enables no primes

41 compositions (the order matters) of integer 7, which with included zeros enable primes, so this sequence has 41 = prime(13) terms

Prime indices (6 primes, 2 squares, 1 cube)

4=2^2, 14, 18, 36=6^2, 48, 53, 65, 67, 82, 174, 188, 198, 202, 216=6^3, 319, 321, 331, 344, 445, 566, 672, 1245, 1346, 1349, 1367, 1460, 1654, 2374, 2385, 2479, 3268, 9696, 9781, 10546, 10552, 10629, 12246, 26809, 93015, 149709, 733339

Links

Table of n, a(n) for n=1..38.

Example

43 = prime(14), 2nd term
1201111 = prime(93015), 39th term
2011111 = prime(149709), 40th term
11110111 = prime(733339), 41st term
Curious 2221 = prime(331) and 331 itself is 7th term of sequence, 1321 = prime(6^3)
4 palindromic primes: 7 = palprime(2^2), 151 = palprime(2^3), 313 = palprime(11), 11311 = palprime(4!)

Crossrefs

A000041, A046704, A075177, A091939, A176009, A176251.

Sequence in context: A301628 A061241 A062337 * A118703 A139832 A139848

Adjacent sequences: A176249 A176250 A176251 * A176253 A176254 A176255

Keyword

base,fini,nonn,uned

Author

Ulrich Krug (leuchtfeuer37(AT)gmx.de), Apr 13 2010

Status

approved