

A107836


Slowest increasing sequence where a(n)+(first digit of a(n)) is prime.


3



1, 10, 12, 16, 18, 21, 27, 29, 34, 38, 43, 49, 54, 56, 61, 65, 67, 72, 76, 81, 89, 92, 94, 98, 100, 102, 106, 108, 112, 126, 130, 136, 138, 148, 150, 156, 162, 166, 172, 178, 180, 190, 192, 196, 198, 209, 221, 225, 227, 231, 237, 239, 249, 255, 261, 267, 269, 275
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OFFSET

1,2


LINKS

Robert Israel, Table of n, a(n) for n = 1..10000


EXAMPLE

1 + 1 = 2, which is prime; 10 + 1 = 11, which is prime; 12 + 1 = 13, which is prime; 16 + 1 = 17, which is prime; 18 + 1 = 19, which is prime; 21 + 2 = 23, which is prime; etc.


MAPLE

select(t > isprime(t + floor(t/10^ilog10(t))), [$1..1000]); # Robert Israel, May 05 2020


MATHEMATICA

Select[ Range[280], PrimeQ[ # + IntegerDigits[ # ][[1]]] &] (* Robert G. Wilson v, Jun 14 2005 *)


CROSSREFS

Sequence in context: A072198 A057485 A162825 * A096128 A334939 A063192
Adjacent sequences: A107833 A107834 A107835 * A107837 A107838 A107839


KEYWORD

base,easy,nonn


AUTHOR

Eric Angelini, Jun 11 2005


EXTENSIONS

Edited, corrected and extended by Robert G. Wilson v, Jun 14 2005


STATUS

approved



