src/main/java/com/wavesplatform/wavesj/Node.java
public List<BlockHeader> getBlockHeaderSeq(int from, int to) throws IOException {
        String path = String.format("/blocks/headers/seq/%s/%s", from, to);
        HttpResponse r = exec(request(path));
        return parse(r, BLOCK_HEADER_LIST);
    }
public List<BlockHeader> getBlockHeaderSeq(int from, int to) throws IOException {
        String path = String.format("/blocks/headers/seq/%s/%s", from, to);
        HttpResponse r = exec(request(path));
        return parse(r, BLOCK_HEADER_LIST);
    }
Returns seq of block headers

@param from start block
@param to   end block
@return sequences of block objects without transactions
@throws IOException if no block exists at the given height