A100763 a(1) = 2; for n>1, a(n) is the least prime with all prime digits which is == 1 (mod a(n-1)).

2, 3, 7, 337, 32353, 7727255227, 23523352753755575323

Offset

1,1

Comments

a(7) > 2*10^19. - Robert G. Wilson v, Nov 27 2004

a(8) > 2*10^32. - Jon E. Schoenfield, Mar 29 2015

Links

Table of n, a(n) for n=1..7.

Example

a(4) = 337, a(5) = 32353 == 1 (mod 337).

Mathematica

a[1] = 2; a[n_] := a[n] = Block[{k = 1, p = a[n - 1]}, While[ !PrimeQ[k*p + 1] || Union[ Join[{2, 3, 5, 7}, IntegerDigits[k*p + 1]]] != {2, 3, 5, 7}, k++ ]; k*p + 1]; Table[ a[n], {n, 6}] (* Robert G. Wilson v, Nov 27 2004 *)

Crossrefs

Sequence in context: A079637 A062662 A084727 * A132538 A334726 A062615

Adjacent sequences: A100760 A100761 A100762 * A100764 A100765 A100766

Keyword

base,nonn

Author

Amarnath Murthy, Nov 25 2004

Extensions

a(6) from Robert G. Wilson v, Nov 27 2004

a(7) from Jon E. Schoenfield, Mar 29 2015

Status

approved