A129630 Numbers n such that sum of digits of n+1 is a prime.

1, 2, 4, 6, 10, 11, 13, 15, 19, 20, 22, 24, 28, 29, 31, 33, 37, 40, 42, 46, 48, 49, 51, 55, 57, 60, 64, 66, 69, 73, 75, 82, 84, 88, 91, 93, 97, 100, 101, 103, 105, 109, 110, 112, 114, 118, 119, 121, 123, 127, 130, 132, 136, 138, 139, 141, 145, 147, 150, 154, 156, 159

Offset

1,2

Links

Table of n, a(n) for n=1..62.

Formula

a(n) = A028834(n) - 1.

Maple

P:=proc(n) local i, k, w; for i from 1 by 1 to n do w:=0; k:=binomial(i+1, i); while k>0 do w:=w+k-(trunc(k/10)*10); k:=trunc(k/10); od; if isprime(w) then print(i); fi; od; end: P(1000);

Mathematica

Select[Range[200], PrimeQ[Total[IntegerDigits[# + 1]]] &]

Crossrefs

Sequence in context: A109133 A056077 A249428 * A026429 A086917 A004789

Adjacent sequences: A129627 A129628 A129629 * A129631 A129632 A129633

Keyword

nonn,base,easy

Author

Paolo P. Lava and Giorgio Balzarotti, May 31 2007

Status

approved