A152604 a(1) = 1; thereafter a(n) is always the smallest integer > a(n-1) not leading to a contradiction, such that any four consecutive digits in the sequence sum up to a prime.

1, 2, 3, 5, 7, 8, 9, 51, 83, 110, 111, 211, 301, 310, 311, 631, 703, 710, 911, 2111, 2113, 2117, 2119, 2153, 2155, 2159, 2171, 2173, 2177, 2179, 2513, 2515, 2519, 2531, 2533, 2537, 2539, 2573, 2575, 2579, 8513, 8515, 8519, 8573, 8579, 8591

Offset: 1

Author

N. J. A. Sloane, Sep 23 2009

Keywords

• nonn
• base

Comments

Computed by Jean-Marc Falcoz.

From a(69)=1100110 onward starts a repeating pattern of length 54. - M. F. Hasler, Oct 16 2009

Links

• Eric Angelini, Chiffres consecutifs dans quelques suites
• E. Angelini, Chiffres consecutifs dans quelques suites [Cached copy, with permission]

Crossrefs

Cf. A158652, A152603..A152609.

Programs

PARI

A152604(n,show_all=0)={my(a);for(i=1,n,if( i<8,a=i+(i>3)+(i>4), my(l3d=if(a>99,a%1000,[789,951,183][i-7])); while( a++, my(t=a+l3d*10^#Str(a));forstep(d=#Str(a)-1,0,-1, isprime(sum(j=d,d+3,t\10^j%10)) & next; a+=10^d-a%10^d-1; next(2)); break)); show_all&print1(a", "));a} \\ M. F. Hasler, Oct 16 2009