A091632 Excess of n + product of digits over next prime associated with A091628.

0, 8, 10, 42, 72, 176, 354, 764, 1516, 3022, 6066, 12268, 24570, 49148, 98246, 196530, 393158, 786406, 1572834, 3145674, 6291440, 12582874, 25165764, 50331634, 100663192, 201326576, 402653180, 805306350, 1610612690, 3221225038

Offset

1,2

Comments

Sequence arising in Farideh Firoozbakht's solution to Prime Puzzle 251 - 23 is the only pointer prime (A089823) not containing the digit "1".

The monotonically increasing value of successive excess (and product of digits (A091629)) strongly suggests that in successive n the digit 1 must be present.

Links

Table of n, a(n) for n=1..30.

Carlos Rivera's Prime Puzzles and Problems Connection, Puzzle 251, Pointer primes

Formula

a(n) = A091630(n) - A091631(n).

Example

a(2) = 235 - 227 = 8.

Crossrefs

Cf. A089823, A091628, A091629, A091630, A091631.

Sequence in context: A367893 A325999 A240036 * A060768 A218464 A060809

Adjacent sequences: A091629 A091630 A091631 * A091633 A091634 A091635

Keyword

base,easy,nonn

Author

Enoch Haga, Jan 24 2004

Extensions

Edited and extended by Ray Chandler, Feb 07 2004

Status

approved