A346489 a(n) is the index of the smallest prime whose digits sum to n-th prime.

1, 2, 3, 4, 10, 19, 24, 46, 109, 430, 669, 3245, 6057, 7837, 33067, 77777, 476643, 601855, 3556550, 5216954, 15739663, 41146179, 189961757, 882206624, 3325059246, 15581005618, 23007498153, 37607875618

Offset: 1

Author

Ilya Gutkovskiy, Jul 19 2021

Keywords

• nonn
• base

Examples

			a(10) = 430 because prime(430) = 2999, 2 + 9 + 9 + 9 = 29 = prime(10) and this is the smallest such number.
		

Crossrefs

Cf. A000040, A000720, A007605, A028834, A046704, A046864, A054750, A075177.

Programs

Mathematica

Module[{nn=522*10^4,tbl},tbl=Table[{n,Total[IntegerDigits[Prime[n]]]},{n,nn}];Table[SelectFirst[tbl,#[[2]]==Prime[n]&],{n,20}]][[;;,1]] (* The program generates the first 20 terms of the sequence. *) (* Harvey P. Dale, Feb 19 2023 *)

Formula

a(n) = A000720(A054750(n)).

a(n) = min {k : A007605(k) = prime(n)}.