A176294 Numbers k such that sum of digits of k = sum of digits of k-th positive nonprime.

1, 15, 16, 17, 18, 19, 44, 45, 46, 47, 48, 116, 117, 118, 119, 245, 246, 290, 291, 292, 293, 294, 374, 375, 376, 425, 426, 427, 428, 429, 431, 432, 433, 434, 435, 436, 437, 438, 439, 441, 486, 487, 488, 489, 527, 528, 529, 580, 581, 582, 627, 628, 629, 684

Offset

1,2

Links

Jinyuan Wang, Table of n, a(n) for n = 1..10000

Example

15 is a term because the 15th positive nonprime in A018252 is 24, and 1 + 5 = 2 + 4 = 6. - Bernard Schott, Feb 04 2019

Maple

A007953 := proc(n) add(d, d=convert(n, base, 10)) ; end proc:
A018252 := proc(n) option remember ; if n = 1 then 1; else for a from procname(n-1)+1 do if not isprime(a) then return a; end if; end do: end if; end proc:
for n from 1 to 900 do if A007953(n) = A007953(A018252(n)) then printf("%d, ", n) ; end if; end do: # R. J. Mathar, Apr 20 2010

Prog

(PARI) k=0; for(n=1, 684, k++; while(isprime(k), k++); if(sumdigits(n)==sumdigits(k), print1(n, ", "))) \\ Jinyuan Wang, Feb 04 2019

Crossrefs

Cf. A018252.

Sequence in context: A363784 A296751 A297281 * A214424 A358043 A090461

Adjacent sequences: A176291 A176292 A176293 * A176295 A176296 A176297

Keyword

nonn,base,less

Author

Juri-Stepan Gerasimov, Apr 14 2010

Extensions

More terms from R. J. Mathar, Apr 20 2010

Status

approved